JP2023506465A - Anti-MerTK antibody and method of use thereof - Google Patents

Abstract

The present disclosure generally provides compositions comprising MerTK polypeptides, e.g., antibodies, e.g., monoclonal antibodies, antibody fragments, etc., that specifically bind to mammalian or human MerTK, and methods for treating such individuals in the treatment of individuals in need thereof. Regarding the use of the composition. [Selection figure] None

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application is based on U.S. Provisional Application No. 62/947,855 filed December 13, 2019, U.S. Provisional Application No. 63/016,821 filed April 28, 2020 , and U.S. Provisional Application No. 63/121,773, filed December 4, 2020, each of which is hereby incorporated by reference in its entirety.

SUBMISSIONS OF SEQUENCE LISTINGS IN ASCII TEXT FILES The contents of the following submissions in ASCII text files are hereby incorporated by reference in their entirety: Sequence Listing in Computer Readable Format (CRF) (Filename: 4503_010PC03_SeqListing_ST25.TXT, Recorded date: December 11, 2020, size: 477,412 bytes).

The present disclosure relates to anti-MerTK antibodies and uses (eg, therapeutic uses) of such antibodies.

Mer tyrosine kinase (MerTK) belongs to the TAM (Tyro3, Axl and MerTK) family of receptor tyrosine kinases. MerTK is a type 1 single transmembrane protein with an extracellular domain with two immunoglobulin (Ig)-like and two fibronectin (FN) type III motifs (Graham et al, 2014, Nat Rev Cancer, 14 :769-785, Rothlin et al, 2015, Annu Rev Immunol, 33:355-391).

Several ligands for MerTK have been identified, including protein S (ProS or ProS1), growth arrest specific gene 6 (Gas6), tabby, tabby-like protein 1 (TULP-1), and galectin-3. MerTK signals from the extracellular space via activation after ligand binding, leading to MerTK tyrosine autophosphorylation (Cummings et al, 2013, Clin Cancer Res, 19:5275-5280, Verma et al, 2011, Mol Cancer Ther, 10:1763-1773), and subsequent ERK- and AKT-related signaling.

MerTK regulates a variety of physiological processes including cell survival, migration, and differentiation. The MerTK ligands ProS and Gas6 contribute to several oncogenic processes such as cell survival, invasion, migration, chemoresistance, and metastasis, and their expression often correlates with poor clinical outcomes. do. In addition, MerTK has been implicated in many cancers and deficiency of MerTK or ProS has been associated with anti-tumor effects (Cook et al, 2013, J Clin Invest, 123:3231-3242, Ubil et al. , 2018, J Clin Invest, 128:2356-2369, Huey et al, 2016, Cancers, 8:101). However, MerTK is also expressed in retinal pigment epithelial cells and plays an important role in clearing outer segments of shed photoreceptor sites in the eye. Loss-of-function mutations in MerTK lead to retinitis pigmentosa and other retinal dystrophies (eg Al-khersan et al, Graefes Arch Clim Exp Ophthalmol, 2017, 255:1613-1619, Lorach et al, Nature Scientific Reports, 2018, 8:11312, Audo et al, Human Mutation, Wiley, 2018, 39:997-913, LaVail et al, Adv Exp Med Biol, 2016, 854:487-493).

MerTK plays a key role in phagocytosis of apoptotic cells by phagocytic cells (efferocytosis), leading to M2-like macrophage polarization, production of anti-inflammatory cytokines, and promotion of an immunosuppressive tumor microenvironment. . Reducing efferocytosis by phagocytic cells increases M1-like macrophage polarization, leading to the production of inflammatory cytokines and an immunoreactive milieu. Modulating efferocytosis may provide an effective means for anti-tumor activity.

Anti-MerTK antibodies have already been disclosed, for example, in International Patent Application Publication Nos. WO2016/106221, WO2016/001830, WO2009/062112, and WO2006/058202, and for example, Dayoub and Brekken, 2020, Cell Communications and Signaling, 18:29, Zhou et al, 20 I, 20 52:1-17, Kedage et al, 2020, MABS, 12:e1685832, Cummings et al, 2014, Oncotarget, 5:10434-10445.
There is a need for new therapeutic anti-MerTK antibodies that are effective in treating conditions such as cancer. The present disclosure meets this need by providing anti-MerTK antibodies effective in mediating anti-tumor immunity, reducing efferocytosis, and promoting M1-like macrophage polarization.
All references cited herein, including patent applications and publications, are hereby incorporated by reference in their entirety.

WO2020/214995 WO2020/076799 WO2020/106461 WO2020/176497 WO2019/084307 WO2019/005756 WO2016/106221 WO2016/001830 WO2009/062112 WO2006/058202

Graham et al, 2014, Nat Rev Cancer, 14:769-785 Rothlin et al, 2015, Annu Rev Immunol, 33:355-391 Cummings et al, 2013, Clin Cancer Res, 19:5275-5280 Verma et al, 2011, Mol Cancer Ther, 10:1763-1773 Cook et al, 2013, J Clin Invest, 123:3231-3242 Ubil et al, 2018, J Clin Invest, 128:2356-2369 Huey et al, 2016, Cancers, 8:101 Al-Khersan et al, Graefes Arch Clim Exp Ophthalmol, 2017, 255: 1613-1619 Lorach et al, Nature Scientific Reports, 2018, 8:11312 Audo et al, Human Mutation, Wiley, 2018, 39:997-913 LaVail et al, Adv Exp Med Biol, 2016, 854:487-493 Dayoub and Brekken, 2020, Cell Communications and Signaling, 18:29 Zhou et al, 2020, Immunity, 52:1-17 Kedage et al, 2020, MABS, 12: e1685832 Cummings et al, 2014, Oncotarget, 5:10434-10445

The present disclosure relates generally to anti-Mer tyrosine kinase (MerTK) antibodies and methods of using such antibodies. The methods provided herein are used to treat individuals with cancer. In some embodiments, the disclosure provides a method of treating an individual with cancer, comprising administering a therapeutically effective amount of an anti-MerTK antibody to an individual in need thereof.

In one aspect, the present disclosure relates to an isolated anti-MerTK antibody that binds to a MerTK protein, said antibody comprising a heavy chain variable region and a light chain variable region, said heavy chain variable region comprising: a) SEQ ID NO: HVR-H1 comprising an amino acid sequence of 83, b) HVR-H2 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 329, 330, 331, 332, and 333, and c) SEQ ID NOs: 138, 334, 335, HVR-H3 comprising an amino acid sequence selected from the group consisting of 336, 337, 338 and 339, wherein said light chain variable region consists of d) SEQ ID NOS: 158, 340, 341, 342, 343 and 344 e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:187; and f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:210.

In one aspect, the present disclosure relates to an isolated anti-MerTK antibody that binds to a MerTK protein, wherein the antibody comprises (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:83, (b) the amino acid sequence of SEQ ID NO:99 (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 138; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 158; (e) HVR- comprising the amino acid sequence of SEQ ID NO: 187 L2, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 83, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 329, (c) (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 158; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) SEQ ID NO: 210. (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 83; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 330; (c) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 138 (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 158; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210; (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 83, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 329, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 138, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210; (a) the amino acid sequence of SEQ ID NO: 83. (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 329; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 138; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 341 (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210; (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 83; HVR-H2 comprising the amino acid sequence of SEQ ID NO:329, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:335, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:341, (e) the amino acid of SEQ ID NO:187 HVR-L2 containing the sequence, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 83, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 331, (c) SEQ ID NO: (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:341; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:187; and (f) the amino acid sequence of SEQ ID NO:210. (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:83; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:329; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:138 (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:342, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:187, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:210, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:83, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:329, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:336, (d) the amino acid of SEQ ID NO:341 (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210; (a) HVR comprising the amino acid sequence of SEQ ID NO: 83. -H1, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:329, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:337, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:343, (e) ) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 83, (b) SEQ ID NO: 332 (c) HVR-H3 containing the amino acid sequence of SEQ ID NO:338; (d) HVR-L1 containing the amino acid sequence of SEQ ID NO:341; (e) containing the amino acid sequence of SEQ ID NO:187 HVR-L2, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:210, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:83, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:333, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:334, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:158, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:187, and (f) sequence HV comprising the amino acid sequence numbered 210 R-L3, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 83, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 332, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 336, ( d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 341, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210, (a) SEQ ID NO: (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 329; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 339; (d) the amino acid sequence of SEQ ID NO: 344. (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210; or (a) HVR-L comprising the amino acid sequence of SEQ ID NO: 83. H1, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 329, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 138, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 158, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:210.

In one aspect, the disclosure relates to an isolated anti-MerTK antibody that binds to a MerTK protein, said antibody comprising a heavy chain variable domain (VH) and a light chain variable domain (VL), wherein said VH and VL are is selected from the group consisting of: a VH comprising the amino acid sequence of SEQ ID NO: 19 and a VL comprising the amino acid sequence of SEQ ID NO: 54, a VH comprising the amino acid sequence of SEQ ID NO: 234 and a VL comprising the amino acid sequence of SEQ ID NO: 247; VH comprising the amino acid sequence of SEQ ID NO: 235 and VL comprising the amino acid sequence of SEQ ID NO: 247, VH comprising the amino acid sequence of SEQ ID NO: 236 and VL comprising the amino acid sequence of SEQ ID NO: 248, VH comprising the amino acid sequence of SEQ ID NO: 236 and VL comprising the amino acid sequence of SEQ ID NO: 249, VH comprising the amino acid sequence of SEQ ID NO: 237 and VL comprising the amino acid sequence of SEQ ID NO: 249, VH comprising the amino acid sequence of SEQ ID NO: 238 and VL comprising the amino acid sequence of SEQ ID NO: 249, VH comprising the amino acid sequence of SEQ ID NO: 239 and VL comprising the amino acid sequence of SEQ ID NO: 250, VH comprising the amino acid sequence of SEQ ID NO: 240 and VL comprising the amino acid sequence of SEQ ID NO: 251, VH comprising the amino acid sequence of SEQ ID NO: 241 and VL comprising the amino acid sequence of SEQ ID NO: 252, VH comprising the amino acid sequence of SEQ ID NO: 242 and VL comprising the amino acid sequence of SEQ ID NO: 249, VH comprising the amino acid sequence of SEQ ID NO: 243 and VL comprising the amino acid sequence of SEQ ID NO: 247, VH comprising the amino acid sequence of SEQ ID NO: 244 and VL comprising the amino acid sequence of SEQ ID NO: 251, VH comprising the amino acid sequence of SEQ ID NO: 245 and VL comprising the amino acid sequence of SEQ ID NO: 253, VH comprising the amino acid sequence of SEQ ID NO: 246 and A VL comprising the amino acid sequence of SEQ ID NO:247, and a VH comprising the amino acid sequence of SEQ ID NO:246 and a VL comprising the amino acid sequence of SEQ ID NO:254.

In one aspect, the present disclosure relates to an isolated anti-MerTK antibody that binds to a MerTK protein, said antibody comprising a heavy chain variable region and a light chain variable region, said heavy chain variable region comprising: a) SEQ ID NO: b) HVR-H2 comprising an amino acid sequence selected from the group consisting of SEQ ID NO: 99 and 329; and c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 139, said The light chain variable region comprises d) HVR-L1 comprising an amino acid sequence selected from the group consisting of SEQ ID NO: 169 and 345, e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 195, and f) the amino acid sequence of SEQ ID NO: 219 Includes HVR-L3 containing sequences.

In one aspect, the present disclosure relates to an isolated anti-MerTK antibody that binds to a MerTK protein, wherein the antibody comprises (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:84, (b) the amino acid sequence of SEQ ID NO:329 (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 139; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 169; (e) HVR- comprising the amino acid sequence of SEQ ID NO: 195 L2, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 219, or (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 84, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 99, ( c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 139, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 345, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 195, and (f) SEQ ID NO: Includes HVR-L3, which contains a 219 amino acid sequence.

In one aspect, the disclosure relates to an isolated anti-MerTK antibody that binds to a MerTK protein, said antibody comprising a heavy chain variable domain (VH) and a light chain variable domain (VL), wherein said VH and VL are is selected from the group consisting of: VH comprising the amino acid sequence of SEQ ID NO:255 and VL comprising the amino acid sequence of SEQ ID NO:257, and VH comprising the amino acid sequence of SEQ ID NO:256 and VL comprising the amino acid sequence of SEQ ID NO:258 .

In one aspect, the present disclosure relates to an isolated anti-MerTK antibody that binds to a MerTK protein, said antibody comprising a heavy chain variable region and a light chain variable region, said heavy chain variable region comprising: a) SEQ ID NO: HVR-H1 comprising an amino acid sequence selected from the group consisting of 95, 346 and 347, b) an amino acid sequence selected from the group consisting of SEQ ID NOS: 119, 348, 349, 350, 351, 352, 353 and 354 and c) HVR-H3 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 151, 355, and 356, wherein the light chain variable region is d) SEQ ID NOs: 181, 341, 357 , and 358, e) HVR-L2 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 187 and 359, and f) SEQ ID NOs: 208, 360, 361. , and HVR-L3 comprising an amino acid sequence selected from the group consisting of 362.

In one aspect, the present disclosure relates to an isolated anti-MerTK antibody that binds to a MerTK protein, wherein the antibody comprises (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:95, (b) the amino acid sequence of SEQ ID NO:119 (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 151; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 181; (e) HVR- comprising the amino acid sequence of SEQ ID NO: 187 L2, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 208, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 346, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 348, (c) ) HVR-H3 comprising the amino acid sequence of SEQ ID NO:355, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:341, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:187, and (f) SEQ ID NO:360 (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 95; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 119; (c) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 355 (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:341; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:361; (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 95, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 349, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 356, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 362; (a) the amino acid sequence of SEQ ID NO: 95. (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 119; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 356; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 341 (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 359; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 362; (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 346; HVR-H2 comprising the amino acid sequence of SEQ ID NO: 119, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 356, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 341, (e) the amino acid of SEQ ID NO: 359 HVR-L2 containing sequences and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:362, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:95, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:350, (c) (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:341; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:359; and (f) HVR-L2 comprising the amino acid sequence of SEQ ID NO:362. HVR-L3 comprising the amino acid sequence, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:347, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:119, (c) HVR comprising the amino acid sequence of SEQ ID NO:356 -H3, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:341, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:359, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:362, ( a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:95, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:119, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:356, (d) SEQ ID NO:341 (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 362; (a) the amino acid sequence of SEQ ID NO: 95. (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:352; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:356; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:341; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 362; (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 95; HVR-H2 comprising the amino acid sequence of SEQ ID NO: 353, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 356, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 341, (e) the amino acid sequence of SEQ ID NO: 359 and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:362, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:346, (b) HVR- comprising the amino acid sequence of SEQ ID NO:354 H2, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:356, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:341, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:359, and (f) ) amino acid sequence of SEQ ID NO:363 (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:346; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:348; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:356 (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:357, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:359, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:362, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:346, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:354, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:356, (d) the amino acid of SEQ ID NO:358 (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 362; or (a) comprising the amino acid sequence of SEQ ID NO: 95. HVR-H1, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 348, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 151, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 181, ( e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:208.

In one aspect, the disclosure relates to an isolated anti-MerTK antibody that binds to a MerTK protein, said antibody comprising a heavy chain variable domain (VH) and a light chain variable domain (VL), wherein said VH and VL are is selected from the group consisting of: a VH comprising the amino acid sequence of SEQ ID NO:33 and a VL comprising the amino acid sequence of SEQ ID NO:68, a VH comprising the amino acid sequence of SEQ ID NO:259 and a VL comprising the amino acid sequence of SEQ ID NO:274; VH comprising the amino acid sequence of SEQ ID NO: 260 and VL comprising the amino acid sequence of SEQ ID NO: 275, VH comprising the amino acid sequence of SEQ ID NO: 261 and VL comprising the amino acid sequence of SEQ ID NO: 276, VH comprising the amino acid sequence of SEQ ID NO: 262 and VL comprising the amino acid sequence of SEQ ID NO: 277, VH comprising the amino acid sequence of SEQ ID NO: 263 and VL comprising the amino acid sequence of SEQ ID NO: 277, VH comprising the amino acid sequence of SEQ ID NO: 264 and VL comprising the amino acid sequence of SEQ ID NO: 277, VH comprising the amino acid sequence of SEQ ID NO: 265 and VL comprising the amino acid sequence of SEQ ID NO: 277, VH comprising the amino acid sequence of SEQ ID NO: 266 and VL comprising the amino acid sequence of SEQ ID NO: 277, VH comprising the amino acid sequence of SEQ ID NO: 267 and VL comprising the amino acid sequence of SEQ ID NO: 278, VH comprising the amino acid sequence of SEQ ID NO: 268 and VL comprising the amino acid sequence of SEQ ID NO: 279, VH comprising the amino acid sequence of SEQ ID NO: 269 and VL comprising the amino acid sequence of SEQ ID NO: 279, VH comprising the amino acid sequence of SEQ ID NO: 264 and VL comprising the amino acid sequence of SEQ ID NO: 280, VH comprising the amino acid sequence of SEQ ID NO: 270 and VL comprising the amino acid sequence of SEQ ID NO: 281, VH comprising the amino acid sequence of SEQ ID NO: 265 and VL comprising the amino acid sequence of SEQ ID NO: 282, VH comprising the amino acid sequence of SEQ ID NO: 264 and VL comprising the amino acid sequence of SEQ ID NO: 283, VH comprising the amino acid sequence of SEQ ID NO: 271 and VL comprising the amino acid sequence of SEQ ID NO: 284, VH comprising the amino acid sequence of SEQ ID NO: 272 and VL comprising the amino acid sequence of SEQ ID NO: 285, VH comprising the amino acid sequence of SEQ ID NO: 271 and VL comprising the amino acid sequence of SEQ ID NO: 286, VH comprising the amino acid sequence of SEQ ID NO: 273 and VL comprising the amino acid sequence of SEQ ID NO:287, VH comprising the amino acid sequence of SEQ ID NO:273 and VL comprising the amino acid sequence of SEQ ID NO:288, and VH comprising the amino acid sequence of SEQ ID NO:273 and the amino acids of SEQ ID NO:289 VL containing sequences.

In one aspect, the present disclosure relates to an isolated anti-MerTK antibody that binds to a MerTK protein, said antibody comprising a heavy chain variable region and a light chain variable region, said heavy chain variable region comprising: a) SEQ ID NO: HVR-H1 comprising a 90 amino acid sequence, b) HVR-H2 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 122, 364, 365, 366, 367 and 368, and c) SEQ ID NOs: 155, 373, 374, and 375, wherein the light chain variable region comprises d) SEQ ID NOs: 184, 376, 377, 378, 379, 380, 381, 382, 383; HVR-L1 comprising an amino acid sequence selected from the group consisting of 384, 385, 386, and 387; L2, and f) HVR-L3 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs:231, 392, 393, and 394.

In one aspect, the present disclosure relates to an isolated anti-MerTK antibody that binds to a MerTK protein, the antibody comprising (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:90, (b) the amino acid sequence of SEQ ID NO:122 (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 184; (e) HVR- comprising the amino acid sequence of SEQ ID NO: 203 L2, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 231, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 364, (c) (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:376; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:388; and (f) SEQ ID NO:231. (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 364; (c) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 155 (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:377; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:231; (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 364, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 374, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:231; (a) the amino acid sequence of SEQ ID NO:95. (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 119; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 356; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 341 (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:359; (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:362; (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:90; HVR-H2 comprising the amino acid sequence of SEQ ID NO:365, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:155, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:276, (e) the amino acid of SEQ ID NO:203 HVR-L2 containing the sequence, and and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:392, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:364, (c) sequence (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:376; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:389; and (f) the amino acid sequence of SEQ ID NO:231. HVR-L3 comprising the sequence, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:364, (c) HVR- comprising the amino acid sequence of SEQ ID NO:155 H3, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:379, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:231, (a) ) HVR-H1 comprising the amino acid sequence of SEQ ID NO:90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:366, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:155, (d) SEQ ID NO:380 (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 203; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 231; (a) comprising the amino acid sequence of SEQ ID NO: 90. HVR-H1, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 364, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 373, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 381, ( e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 203, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 231, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) SEQ ID NO: (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 382; (e) the amino acid sequence of SEQ ID NO: 203. and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:231, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:368. (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 383, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 203, and (f) H comprising the amino acid sequence of SEQ ID NO:231 VR-L3, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 364, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 374, ( d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 384, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 203, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 231, (a) SEQ ID NO: HVR-H1 comprising the amino acid sequence of 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:368, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:155, (d) the amino acid sequence of SEQ ID NO:376 (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:393; (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:90 , (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 364, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 378, (e) sequence (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:231; (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:90; (b) the amino acid sequence of SEQ ID NO:368. (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 376; (e) HVR- comprising the amino acid sequence of SEQ ID NO: 203 L2, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:231, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:369, (c) (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 378; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 203; and (f) SEQ ID NO: 394. (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 370; (c) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 155 (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:378; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:394; (a) the amino acid sequence of SEQ ID NO:90 (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 371; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 178 (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203; (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:394; (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:90; HVR-H2 comprising the amino acid sequence of SEQ ID NO:368, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:155, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:385, (e) the amino acid of SEQ ID NO:203 HVR-L2 comprising the sequence, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:394, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:90, (b) HVR comprising the amino acid sequence of SEQ ID NO:368. -H2, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 378, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 203, and ( f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:395, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:368, (c) SEQ ID NO:155 (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 378; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 390; and (f) the amino acid sequence of SEQ ID NO: 394. (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:90; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:372; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:155; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:378, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:391, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:394, (a) sequence (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:368; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:375; (d) the amino acid sequence of SEQ ID NO:386 (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:394; or (a) HVR comprising the amino acid sequence of SEQ ID NO:90. -H1, (b) SEQ ID NO:36 (c) HVR-H3 containing the amino acid sequence of SEQ ID NO: 155; (d) HVR-L1 containing the amino acid sequence of SEQ ID NO: 387; (e) the amino acid sequence of SEQ ID NO: 203. and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:394.

In one aspect, the disclosure relates to an isolated anti-MerTK antibody that binds to a MerTK protein, said antibody comprising a heavy chain variable domain (VH) and a light chain variable domain (VL), wherein said VH and VL are is selected from the group consisting of: a VH comprising the amino acid sequence of SEQ ID NO:37 and a VL comprising the amino acid sequence of SEQ ID NO:72, a VH comprising the amino acid sequence of SEQ ID NO:290 and a VL comprising the amino acid sequence of SEQ ID NO:309; VH comprising the amino acid sequence of SEQ ID NO: 291 and VL comprising the amino acid sequence of SEQ ID NO: 310, VH comprising the amino acid sequence of SEQ ID NO: 292 and VL comprising the amino acid sequence of SEQ ID NO: 311, VH comprising the amino acid sequence of SEQ ID NO: 293 and VL comprising the amino acid sequence of SEQ ID NO: 312, VH comprising the amino acid sequence of SEQ ID NO: 294 and VL comprising the amino acid sequence of SEQ ID NO: 313, VH comprising the amino acid sequence of SEQ ID NO: 295 and VL comprising the amino acid sequence of SEQ ID NO: 314, VH comprising the amino acid sequence of SEQ ID NO: 296 and VL comprising the amino acid sequence of SEQ ID NO: 315, VH comprising the amino acid sequence of SEQ ID NO: 290 and VL comprising the amino acid sequence of SEQ ID NO: 316, VH comprising the amino acid sequence of SEQ ID NO: 297 and VL comprising the amino acid sequence of SEQ ID NO: 317, VH comprising the amino acid sequence of SEQ ID NO: 298 and VL comprising the amino acid sequence of SEQ ID NO: 318, VH comprising the amino acid sequence of SEQ ID NO: 292 and VL comprising the amino acid sequence of SEQ ID NO: 319, VH comprising the amino acid sequence of SEQ ID NO: 299 and VL comprising the amino acid sequence of SEQ ID NO: 320, VH comprising the amino acid sequence of SEQ ID NO: 300 and VL comprising the amino acid sequence of SEQ ID NO: 311, VH comprising the amino acid sequence of SEQ ID NO: 301 and VL comprising the amino acid sequence of SEQ ID NO: 321, VH comprising the amino acid sequence of SEQ ID NO: 302 and VL comprising the amino acid sequence of SEQ ID NO: 322, VH comprising the amino acid sequence of SEQ ID NO: 303 and VL comprising the amino acid sequence of SEQ ID NO: 311, VH comprising the amino acid sequence of SEQ ID NO: 304 and VL comprising the amino acid sequence of SEQ ID NO: 322, VH comprising the amino acid sequence of SEQ ID NO: 305 and VL comprising the amino acid sequence of SEQ ID NO: 322, VH comprising the amino acid sequence of SEQ ID NO: 301 and VL comprising the amino acid sequence of SEQ ID NO:323, VH comprising the amino acid sequence of SEQ ID NO:301 and VL comprising the amino acid sequence of SEQ ID NO:324, VH comprising the amino acid sequence of SEQ ID NO:301 and the amino acid sequence of SEQ ID NO:325 VH comprising the amino acid sequence of SEQ ID NO:306 and VL comprising the amino acid sequence of SEQ ID NO:326, VH comprising the amino acid sequence of SEQ ID NO:307 and VL comprising the amino acid sequence of SEQ ID NO:327, and the amino acid sequence of SEQ ID NO:308 and a VL comprising the amino acid sequence of SEQ ID NO:328.

In one aspect, the present disclosure relates to an isolated anti-MerTK antibody that binds to a MerTK protein, said antibody comprising a heavy chain variable region and a light chain variable region, said heavy chain variable region comprising SEQ ID NO:75, from the group consisting of 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, and 98 HVR-H1, SEQ ID NO: 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, comprising a selected amino acid sequence , 118, 119, 120, 121, 122, 123, and 124; , 134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154,155,156, and 157 wherein the light chain variable region comprises an amino acid sequence selected from the group , 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, and 186, SEQ ID NO: an HVR comprising an amino acid sequence selected from the group consisting of -L2 and SEQ ID NOs: 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227, 228, HVR-L3 comprising an amino acid sequence selected from the group consisting of 229, 230, 231, 232 and 233.

In one aspect, the disclosure relates to an isolated anti-MerTK antibody that binds to a MerTK protein, the antibody comprising HVR-H1, HVR-H2, HVR-H3, HVR-L1, HVR-L2, and HVR- L3s, which have the amino acid sequences (i) SEQ ID NOs: 75, 99, 125, 158, 187, and 207, respectively; (ii) SEQ ID NOs: 76, 100, 126, 159, 187, and 208, respectively; iii) SEQ. 129, 161, 189, and 211, (vi) SEQ ID NOs: 75, 103, 130, 158, 187, and 212, respectively; (vii) SEQ ID NOs: 77, 101, 127, 162, 188, and 209, respectively; viii) SEQ. 133, 165, 191, and 215, (xi) SEQ ID NOs: 81, 106, 134, 166, 192, and 216, respectively; (xii) SEQ ID NOs: 82, 107, 135, 167, 193, and 217, respectively; xiii) SEQ. 138, 158, 187, and 210, (xvi) SEQ ID NOs: 84, 99, 139, 169, 195, and 219, respectively; (xvii) SEQ ID NOs: 85, 99, 140, 170, 196, and 220, respectively; xviii) SEQ. 143, 173, 191, and 223, (xxi) SEQ ID NOs: 89, 111, 143, 173, 198, and 221, respectively; (xxii) SEQ ID NOs: 90, 112, 144, 174, 199, and 224, respectively; xxiii) SEQ ID NOS: 91, 113, 145, 175, 200, and 225, respectively, (xxiv) that SEQ. , 178, 188, and 209, (xxvii) SEQ ID NOs: 94, 117, 149, 179, 195, and 228, respectively; (xxviii) SEQ ID NOs: 95, 118, 150, 180, 187, and 229, respectively; ) SEQ. , 183, 202, and 230, (xxxii) SEQ ID NOs: 96, 121, 154, 181, 187, and 210, respectively (xxxiii) SEQ ID NOs: 90, 122, 155, 184, 203, and 231, respectively (xxxiv ) SEQ ID NOs: 90, 122, 155, 184, 203, and 231, respectively; (xxxv) SEQ ID NOs: 97, 123, 156, 185, 204, and 232, respectively; 157, 186, 205, and 233.

In some embodiments that may be combined with any of the embodiments provided herein, the anti-MerTK antibody of this disclosure is an isolated antibody that binds to MerTK protein, wherein the antibody binds to MTK-01 , MTK-02, MTK-03, MTK-04, MTK-05, MTK-06, MTK-07, MTK-08, MTK-09, MTK-10, MTK-11, MTK-12, MTK-13, MTK -14, MTK-15, MTK-16, MTK-17, MTK-18, MTK-19, MTK-20, MTK-21, MTK-22, MTK-23, MTK-24, MTK-25, MTK-26 , MTK-27, MTK-28, MTK-29, MTK-30, MTK-31, MTK-32, MTK-33, MTK-34, MTK-35, or MTK-36 antibody HVR-H1, HVR-H2 , HVR-H3, HVR-L1, HVR-L2 and HVR-L3 sequences. In some embodiments, the HVR is HVR as defined by Kabat, HVR as defined by Chothia, or HVR as defined by AbM.

In some embodiments that may be combined with any of the embodiments provided herein, the anti-MerTK antibody of this disclosure is an isolated antibody that binds to MerTK protein, wherein the antibody binds to MTK-15 .1, MTK-15.2, MTK-15.3, MTK-15.4, MTK-15.5, MTK-15.6, MTK-15.7, MTK-15.8, MTK-15.9 , MTK-15.10, MTK-15.11, MTK-15.12, MTK-15.13, MTK-15.14 and MTK-15.15, MTK-16.1 and MTK-16.2, MTK-29.1, MTK-29.2, MTK-29.3, MTK-29.4, MTK-29.5, MTK-29.6, MTK-29.7, MTK-29.8, MTK- 29.9, MTK-29.10, MTK-29.11, MTK-29.12, MTK-29.13, MTK-29.14, MTK-29.15, MTK-29.16, MTK-29. 17, MTK-29.18, MTK-29.19, MTK-29.20, and MTK-29.21, MTK-33.1, MTK-33.2, MTK-33.3, MTK-33.4 , MTK-33.5, MTK-33.6, MTK-33.7, MTK-33.8, MTK-33.9, MTK-33.10, MTK-33.11, MTK-33.12, MTK -33.13, MTK-33.14, MTK-33.15, MTK-33.16, MTK-33.17, MTK-33.18, MTK-33.19, MTK-33.20, MTK-33 .21, MTK-33.22, MTK-33.23, or MTK-33.24 antibody HVR-H1, HVR-H2, HVR-H3, HVR-L1, HVR-L2 and HVR-L3 sequences. In some embodiments, the HVR is HVR as defined by Kabat, HVR as defined by Chothia, or HVR as defined by AbM.

In some embodiments that may be combined with any of the embodiments provided herein, the anti-MerTK antibody of this disclosure is an isolated antibody that binds to MerTK protein, wherein the antibody comprises a variable heavy chain SEQ ID NOs: 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 , 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, and 39.

In some embodiments that may be combined with any of the embodiments provided herein, the anti-MerTK antibody of this disclosure is an isolated antibody that binds to MerTK protein, wherein the antibody comprises a variable heavy chain A region comprising an amino acid sequence selected from the group consisting of SEQ ID NOs:234-246, 255, 256, 259-379, and 290-308.

In some embodiments that may be combined with any of the embodiments provided herein, the anti-MerTK antibody of this disclosure is an isolated antibody that binds to MerTK protein, wherein the antibody comprises a variable light chain 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58 , 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, and 74.

In some embodiments that may be combined with any of the embodiments provided herein, the anti-MerTK antibody of this disclosure is an isolated antibody that binds to MerTK protein, wherein the antibody comprises a variable light chain A region comprising an amino acid sequence selected from the group consisting of SEQ ID NOs:247-254, 257, 258, 274-289, and 309-328.

In some embodiments that may be combined with any of the embodiments provided herein, the anti-MerTK antibody of this disclosure is an isolated antibody that binds to MerTK protein, wherein the antibody comprises a variable heavy chain and a light chain variable region, wherein the heavy chain variable region comprises 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, and 39, said light chain comprising an amino acid sequence selected from The variable regions are SEQ ID NOS: 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, and 74.

In some embodiments that may be combined with any of the embodiments provided herein, the anti-MerTK antibody of this disclosure is an isolated antibody that binds to MerTK protein, wherein the antibody comprises a variable heavy chain and a light chain variable region, the heavy chain variable region comprising an amino acid sequence selected from 234-246, 255, 256, 259-379, and 290-308, the light chain variable region comprising SEQ ID NO: Amino acid sequences selected from 247-254, 257, 258, 274-289, and 309-328.

In some embodiments that may be combined with any of the embodiments provided herein, the anti-MerTK antibody of this disclosure is an isolated antibody that binds to a MerTK protein, the heavy chain variable region of said antibody and light chain variable regions are represented by SEQ ID NOs: 5 and 40, respectively, SEQ ID NOs: 6 and 41, respectively, SEQ ID NOs: 7 and 42, respectively, SEQ ID NOs: 8 and 43, respectively, SEQ ID NOs: 9 and 44, respectively. SEQ ID NOs: 10 and 45, respectively, SEQ ID NOs: 11 and 46, respectively, SEQ ID NOs: 12 and 47, respectively, SEQ ID NOs: 13 and 48, respectively, SEQ ID NOs: 14 and 49, respectively, SEQ ID NOs: 15 and 50, respectively, SEQ ID NO: 16 and 51, respectively, SEQ ID NOs: 17 and 52, respectively, SEQ ID NOs: 18 and 53, respectively, SEQ ID NOs: 19 and 54, respectively, SEQ ID NOs: 20 and 55, respectively, SEQ ID NOs: 21 and 56, respectively, SEQ ID NOs: 22 and 57, respectively , SEQ ID NOs: 23 and 58, respectively, SEQ ID NOs: 24 and 59, respectively, SEQ ID NOs: 25 and 60, respectively, SEQ ID NOs: 26 and 61, respectively, SEQ ID NOs: 27 and 62, respectively, SEQ ID NOs: 28 and 63, respectively , SEQ ID NOs: 29 and 64, respectively, SEQ ID NOs: 30 and 65, respectively, SEQ ID NOs: 31 and 66, respectively, SEQ ID NOs: 32 and 67, respectively, SEQ ID NOs: 33 and 68, respectively, SEQ ID NOs: 34 and 69, respectively, sequences 35 and 70, respectively, SEQ ID NOs: 36 and 71, respectively, SEQ ID NOs: 37 and 72, respectively, SEQ ID NOs: 38 and 73, respectively, and SEQ ID NOs: 39 and 74, respectively.

In one aspect, the present disclosure relates to an isolated antibody that binds to a MerTK protein, wherein the antibody binds to MerTK and thus binds to one or more of the antibodies of any of the embodiments herein. competitively inhibit

In another aspect, the disclosure relates to an isolated antibody that binds to a MerTK protein, wherein the antibody binds to an epitope of MerTK that is essentially the same as or overlaps with the antibody of any of the embodiments herein. .

In certain embodiments that may be combined with any of the embodiments herein, said MerTK protein is a mammalian or human protein. In certain embodiments that may be combined with any of the embodiments herein, said MerTK protein is a wild-type protein. In certain embodiments that may be combined with any of the embodiments herein, said MerTK protein is a naturally occurring variant. In certain embodiments that may be combined with any of the embodiments herein, the anti-MerTK antibody binds to human MerTK and cynomolgus monkey MerTK and/or mouse MerTK. In certain embodiments that may be combined with any of the embodiments herein, the anti-MerTK antibody binds human MerTK and mouse MerTK, binds human MerTK and cynomolgus monkey MerTK, or human MerTK, mouse Binds to MerTK and cynomolgus monkey MerTK.

In some embodiments that may be combined with any of the embodiments herein, the anti-MerTK antibodies of this disclosure inhibit or reduce binding of one or more ligands to MerTK. In some embodiments that may be combined with any of the embodiments herein, the anti-MerTK antibodies of the disclosure inhibit or reduce binding of ProS to MerTK. In certain embodiments that may be combined with any of the embodiments herein, the anti-MerTK antibodies of the disclosure reduce binding of ProS to MerTK by at least 20%, at least 25%, at least 30%, at least 40% %, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95% inhibition or reduction. In some embodiments that may be combined with any of the embodiments herein, an anti-MerTK antibody of the disclosure inhibits or reduces binding of ProS to MerTK with an IC50 value of 0.58 nM to 25.9 nM. . In some embodiments that may be combined with any of the embodiments herein, the anti-MerTK antibodies of this disclosure exhibit binding of ProS to MerTK with IC50 values of 0.58 nM to 1 nM, 1 nM to 2.5 nM, Inhibits or reduces at 2.5 nM to 5 nM, 5 nM to 10 nM, or 10 nM to 25 nM.

In some embodiments that may be combined with any of the embodiments herein, the anti-MerTK antibodies of the disclosure inhibit or reduce binding of Gas6 to MerTK. In some embodiments that may be combined with any of the embodiments herein, the anti-MerTK antibodies of this disclosure reduce binding of Gas6 to MerTK by at least 20%, at least 25%, at least 30%, at least 40% %, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95% inhibition or reduction. In some embodiments that may be combined with any of the embodiments herein, an anti-MerTK antibody of the disclosure inhibits or reduces binding of Gas6 to MerTK with an IC50 value of 0.29 nM to 32 nM. In some embodiments that may be combined with any of the embodiments herein, the anti-MerTK antibodies of this disclosure exhibit binding of Gas6 to MerTK with IC50 values of 0.29 nM to 1 nM, 1 nM to 5 nM, 5 nM to 5 nM. Inhibits or reduces at 10 nM, 10 nM to 25 nM, or 25 nM to 32 nM.

In some embodiments that may be combined with any of the embodiments herein, an anti-MerTK antibody of the disclosure inhibits or reduces binding of Gas6 to MerTK and inhibits or reduces binding of ProS to MerTK. Reduce. In some embodiments that may be combined with any of the embodiments herein, an anti-MerTK antibody of the disclosure inhibits or reduces binding of Gas6 to MerTK and inhibits binding of ProS to MerTK by at least 20%, at least 25%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95%, the antibody inhibits or reduces Gas6 reduces or inhibits binding to MerTK by at least 20%, at least 25%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95% . In some embodiments that may be combined with any of the embodiments herein, an anti-MerTK antibody of the disclosure inhibits or reduces binding of Gas6 to MerTK and reduces binding of ProS to MerTK by an IC50 The antibody reduces or inhibits binding of Gas6 to MetTK with IC50 values of 0.29 nM to 32 nM.

In some embodiments that may be combined with any of the embodiments herein, an anti-MerTK antibody of the disclosure inhibits or reduces binding of ProS to MerTK and also reduces inhibition of binding of Gas6 to MerTK Neither.

In some embodiments that may be combined with any of the embodiments herein, the anti-MerTK antibodies of the disclosure do not inhibit or reduce binding of ProS to MerTK and do not inhibit binding of Gas6 to MerTK. .

In some embodiments that may be combined with any of the embodiments herein, the anti-MerTK antibodies of the present disclosure reduce Gas6-mediated phosphorylation of AKT. In some embodiments that may be combined with any of the embodiments herein, an anti-MerTK antibody of the present disclosure reduces Gas6-mediated phosphorylation of AKT with an IC50 value of 0.019 nM to 7.74 nM. . In some embodiments, which may be combined with any of the embodiments herein, the anti-MerTK antibodies of the present disclosure inhibit Gas6-mediated phosphorylation of AKT with IC50 values of 0.019 nM to 0.25 nM, 0.25 nM. 25 nM to 0.5 nM, 0.5 nM to 1 nM, 1 nM to 2.5 nM, 2.5 nM to 5 nM, or 5 nM to 7.74 nM.

In some embodiments that may be combined with any of the embodiments herein, an anti-MerTK antibody of the disclosure binds to human MerTK with a binding affinity of 1.4 nM to 81 nM. In some embodiments that may be combined with any of the embodiments herein, the anti-MerTK antibodies of the disclosure bind to human MerTK with binding affinities of 1.6 nM to 107 nM. In some embodiments that may be combined with any of the embodiments herein, an anti-MerTK antibody of the disclosure binds to human MerTK with a binding affinity of 30 nM to 186 nM.

In some embodiments that may be combined with any of the embodiments herein, the anti-MerTK antibodies of the disclosure reduce or inhibit binding of Gas6 to MerTK in reducing or inhibiting binding of ProS to MerTK. at least 1.7 times, at least 2.3 times, at least 2.4 times, at least 5 times, at least 7.7 times, or at least 8.5 times more effective than in

In some embodiments that may be combined with any of the embodiments provided herein, an anti-MerTK antibody of the disclosure reduces or reduces (eg, by at least 50%) efferocytosis by phagocytic cells. In some embodiments that may be combined with any of the embodiments provided herein, an anti-MerTK antibody of the disclosure reduces efferocytosis by phagocytic cells by at least 60%, at least 70%, at least 80%, at least 90%, or at least 95% reduction or reduction. In some embodiments that may be combined with any of the embodiments provided herein, an anti-MerTK antibody of the disclosure reduces or reduces efferocytosis by phagocytic cells with an IC50 value of 0.13 nM to 30 nM. . In some embodiments that may be combined with any of the embodiments provided herein, an anti-MerTK antibody of this disclosure reduces efferocytosis by phagocytic cells with IC50 values of 0.13 nM to 1 nM, 1 nM to 5 nM, Decrease or decrease from 5 nM to 10 nM, or from 10 nM to 30 nM. In some embodiments, the phagocyte is a macrophage. In some embodiments, the phagocytic cells are tumor-associated macrophages. In some embodiments, the phagocytic cells are dendritic cells.

In some embodiments that may be combined with any of the embodiments provided herein, anti-MerTK antibodies of the disclosure increase or induce M1-like macrophage polarization. In some embodiments that may be combined with any of the embodiments provided herein, an anti-MerTK antibody of the disclosure increases inflammatory cytokine production, expression and/or secretion. In certain embodiments, the inflammatory cytokine is tumor necrosis factor (TNF), interferon (IFN), or interleukin-12 (IL-12). In certain embodiments, the inflammatory cytokine is chemokine (CXC motif) ligand 1 (CXCL-1, KC), monocyte chemoattractant protein-1 (MCP1, CCL2), macrophage inflammatory protein -1-alpha (MIP-1α, CCL3), macrophage inflammatory protein-1-beta (MIP-1β, CCL4), or interleukin-6 (IL-6). In some embodiments that may be combined with any of the embodiments provided herein, an anti-MerTK antibody of the disclosure increases in vitro production, expression, and/or secretion of inflammatory cytokines. In some embodiments that may be combined with any of the embodiments provided herein, anti-MerTK antibodies of the disclosure increase in vivo production, expression, and/or secretion of inflammatory cytokines.

In some embodiments that may be combined with any of the embodiments herein, the anti-MerTK antibodies of this disclosure are monoclonal antibodies. In some embodiments that may be combined with any of the embodiments herein, the antibody is a human antibody. In some embodiments that may be combined with any of the embodiments herein, the antibody is a humanized antibody. In some embodiments that may be combined with any of the embodiments herein, the antibody is a bispecific antibody. In some embodiments that may be combined with any of the embodiments herein, the antibody is a multivalent antibody. In some embodiments that may be combined with any of the embodiments herein, the antibody is a chimeric antibody.

In one aspect, the disclosure relates to an isolated anti-MerTK antibody that binds to a MerTK protein, wherein the antibody is a humanized form of the anti-MerTK antibody provided herein.

In some embodiments that may be combined with any of the embodiments herein, the anti-MerTK antibodies of the disclosure are of the IgG, IgM, or IgA class. In some embodiments, the antibody is of the IgG class and has an IgG1, IgG2, or IgG4 isotype. In some embodiments, the antibody is of the IgG1 isotype having an Fc amino acid sequence selected from the group consisting of SEQ ID NOs:396, 397, 398, 399, 400, and 401.

In certain embodiments that may be combined with any of the embodiments herein, the antibody is a full length antibody. In certain embodiments that may be combined with any of the embodiments herein, the antibody is an antibody fragment. In certain embodiments that may be combined with any of the embodiments herein, the antibody is an antibody fragment that binds to an epitope of human MerTK or mammalian MerTK protein. In certain embodiments that may be combined with any of the embodiments herein, the antibody fragment is a Fab, Fab', Fab'-SH, F(ab')2, Fv, or scFv fragment.

In another aspect, the disclosure relates to an isolated nucleic acid comprising a nucleic acid sequence encoding the anti-MerTK antibody of any of the preceding embodiments. In some embodiments, the disclosure relates to vectors comprising the nucleic acid of any of the preceding embodiments. In some embodiments, the disclosure relates to an isolated host cell comprising the nucleic acid of any of the preceding embodiments or the vector of any of the preceding embodiments. In some embodiments, the present disclosure provides (i) a nucleic acid comprising a nucleic acid sequence encoding the VH of the anti-MerTK antibody of any of the preceding embodiments and (ii) a nucleic acid encoding the VL of the anti-MerTK antibody An isolated host cell containing a nucleic acid containing the sequence.

In another aspect, the disclosure relates to a method of producing an antibody that binds to a human MerTK antibody, said method comprising culturing the host cell of any of the preceding embodiments so that said anti-MerTK antibody is produced. include. In certain embodiments, the method further comprises collecting anti-MerTK antibodies produced by the cells.

In another aspect, the disclosure relates to a pharmaceutical composition comprising the anti-MerTK antibody of any one of the preceding embodiments and a pharmaceutically acceptable carrier.

In one aspect, the present disclosure relates to a method of treating an individual with cancer, comprising administering to an individual in need thereof a therapeutically effective amount of the anti-MerTK antibody of any of the preceding embodiments. include. In some embodiments, the cancer is colon cancer, ovarian cancer, liver cancer, or endometrial cancer. In some embodiments, the cancer is sarcoma, bladder cancer, breast cancer, colon cancer, endometrial cancer, kidney cancer, renal cancer, leukemia, lung cancer, non-small cell lung cancer, melanoma, lymphoma, pancreatic cancer, prostate cancer, ovarian cancer, gastric cancer, thyroid cancer, uterine cancer, liver cancer, cervical cancer, testicular cancer, squamous cell carcinoma, glioma, glioblastoma, adenoma, and neuroblastoma Selected from cell tumors. In some embodiments, the cancer is selected from glioblastoma multiforme, bladder cancer, and esophageal cancer. In some embodiments, the cancer is triple negative breast cancer. In some embodiments, the cancer can be a primary tumor. In some embodiments, the cancer may be a secondary site metastatic tumor from any of the above cancer types. In some embodiments, the anti-MerTK antibodies of the present disclosure are useful for treating a MerTK-expressing cancer in a subject in need thereof. In some embodiments, administration of an anti-MerTK antibody of the disclosure that reduces efferocytosis does not result in retinal lesions in the individual. In some embodiments, the method further comprises administering (eg, simultaneously or sequentially) an anti-PD-L1 antibody, an anti-PD-L2 antibody, or an anti-PD antibody to the individual.

In one aspect, the present disclosure relates to a method of detecting MerTK in a sample, said method comprising contacting said sample with the anti-MerTK antibody of any of the preceding embodiments; and further comprising detecting binding of said antibody to MerTK in said sample.

It is to be understood that one, some, or all of the features of the various embodiments described herein can be combined to form other embodiments of the disclosure. These and other aspects of the disclosure will be apparent to those skilled in the art. These and other aspects of the disclosure are further described by the detailed description below.

Data showing FACS analysis of expression of human MerTK in dendritic cells (DC) and macrophages from two human donors. Data showing FACS analysis of human MerTK expression in various cell lines including A375, THP-1, U937, SK-MEL-5, and CHO-huMerTK OE cells are shown. Figure 2 shows data showing FACS analysis of human MerTK expression in monocytes, macrophages, and dendritic cells from healthy human subjects or from ovarian, liver, or endometrial tumors from human subjects. FIG. 2 shows data showing the effect of anti-MerTK antibodies of the disclosure on reducing efferocytosis in human macrophages. FIG. 4 shows data demonstrating the effect of anti-MerTK antibodies of the present disclosure on reducing efferocytosis in mouse bone marrow-derived macrophages. FIG. 4 shows data demonstrating that anti-MerTK antibodies of the disclosure bind to SK-MEL-5 cells. FIG. 2 shows data showing that anti-MerTK antibodies of the disclosure dose-dependently block the binding of Gas6 ligand to human MerTK. FIG. 4 shows data showing that anti-MerTK antibodies of the disclosure dose-dependently block binding of ProS ligands to human MerTK. FIG. 4 shows data showing the results of epitope binning of anti-MerTK antibodies of the disclosure. A and B present data showing that anti-MerTK antibody treatment alone or in combination with anti-PD-L1 antibody treatment reduced tumor growth in vivo. FIG. 4 shows data showing changes in levels of MCP1 in human macrophages after overnight treatment with anti-MerTK antibodies of the disclosure. Figure 3 shows data showing changes in levels of MIP-1α in human macrophages after overnight treatment with anti-MerTK antibodies of the disclosure. FIG. 4 shows data showing changes in levels of MIP-1β in human macrophages after overnight treatment with anti-MerTK antibodies of the disclosure. FIG. 4 shows data showing changes in levels of TNF in human macrophages after overnight treatment with anti-MerTK antibodies of the disclosure. A and B present data demonstrating reduced tumor growth in mice administered anti-PDL1 antibodies in combination with anti-MerTK antibodies of the present disclosure. FIG. 4 shows data demonstrating reduced tumor growth in mice administered anti-PDL1 antibodies in combination with anti-MerTK antibodies of the present disclosure. A, B, C, and D show data plotted using a linear scale y-axis showing differences in tumor growth rates in mice administered anti-PDL1 antibodies in combination with anti-MerTK antibodies of the present disclosure. A, B, C, and D show data plotted using a log2 scaled y-axis showing differences in tumor growth rates in mice administered an anti-PDL1 antibody in combination with an anti-MerTK antibody of the present disclosure. FIG. 4 shows data showing survival curves of tumor-bearing mice administered anti-PDL1 antibodies in combination with anti-MerTK antibodies of the present disclosure. FIG. 4 shows data showing changes in levels of chemokine (CXC motif) ligand 1 (CXCL-1, KC) in plasma from mice following administration of an anti-MerTK antibody of the disclosure. FIG. 4 shows data showing changes in levels of monocyte chemoattractant protein-1 (MCP1, CCL2) in plasma from mice after administration of an anti-MerTK antibody of the disclosure. FIG. 4 shows data showing changes in macrophage inflammatory protein-1-alpha (MIP-1α, CCL3) levels in plasma from mice after administration of an anti-MerTK antibody of the disclosure. FIG. 4 shows data showing changes in levels of macrophage inflammatory protein-1-beta (MIP-1β, CCL4) in plasma from mice following administration of anti-MerTK antibodies of the disclosure. FIG. 4 presents data showing changes in levels of interleukin-6 (IL-6) in plasma from mice following administration of an anti-MerTK antibody of the disclosure. A, B, C, and D, data showing changes in levels of MCP1, MIP-1β, tumor necrosis factor (TNF), and interferon (IFN) in plasma from cynomolgus monkeys administered anti-MerTK antibodies of the present disclosure. indicate. A and B present data showing changes in the ratio of phosphorylated AKT (pAKT) to total AKT (tAKT) in cells treated with various anti-MerTK antibodies of the present disclosure. FIG. 4 shows data showing changes in tumor volume in vivo in the MC38 tumor mouse model in animals administered anti-PDL-1 antibodies in combination with various anti-MerTK antibodies of the present disclosure. FIG. 4 shows data showing changes in tumor volume in vivo in the MC38 tumor mouse model in animals administered anti-PDL-1 antibodies in combination with various anti-MerTK antibodies of the present disclosure. FIG. 4 shows data showing changes in tumor volume in vivo in the MC38 tumor mouse model in animals administered anti-PDL-1 antibodies in combination with various anti-MerTK antibodies of the present disclosure. FIG. 4 shows data showing changes in tumor volume in vivo in the MC38 tumor mouse model in animals administered anti-PDL-1 antibodies in combination with various anti-MerTK antibodies of the present disclosure. FIG. 4 shows data showing changes in tumor volume in vivo in the MC38 tumor mouse model in animals administered anti-PDL-1 antibodies in combination with various anti-MerTK antibodies of the present disclosure. FIG. 2 shows data showing the binding equilibrium dissociation constants (K _D ) of anti-MerTK antibodies of the present disclosure to human (hu), mouse (mu), and cynomolgus monkey (cy) MerTK proteins.

The present disclosure relates to anti-MerTK antibodies (e.g., monoclonal antibodies), methods of making and using such antibodies, pharmaceutical compositions comprising such antibodies, nucleic acids encoding such antibodies, and host cells comprising nucleic acids encoding such antibodies. .

The techniques and procedures described or referenced herein are generally well understood by those of ordinary skill in the art and can be performed using conventional methods, eg, Sambrook et al. Molecular Cloning: A Laboratory Manual 3d edition (2001) Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.G. Y. , Current Protocols in Molecular Biology (FM Ausubel, et al. eds., (2003), Monoclonal Antibodies: A Practical Approach (P. Shepherd and C. Dean, eds., Oxford University 0, 0). It is commonly adopted using widely used methods such as

I. DEFINITIONS The terms "MerTK" or "MerTK polypeptide" or "MerTK protein" are used interchangeably herein, unless otherwise specified, and are used in mammals, e.g., primates (e.g., humans and cynomolgus monkeys (cynos)). and any naturally occurring MerTK from any vertebrate, including rodents (eg, mice and rats). MerTK is also called c-mer, MER, protooncogene c-Mer, receptor tyrosine kinase MerTK, tyrosine protein kinase Mer, STK kinase, RP38, and MGC133349. In some embodiments, the term encompasses both wild-type sequences and naturally occurring variant sequences, such as splice or allelic variants. In some embodiments, the term encompasses "full-length," unprocessed MerTK and any form of MerTK that results from processing within the cell. In some embodiments, the MerTK is human MerTK. As used herein, the term "human MerTK" refers to a polypeptide having the amino acid sequence of SEQ ID NO:1.

The terms "anti-MerTK antibody,""antibody that binds to MerTK," and "antibody that specifically binds to MerTK" are capable of binding to MerTK with sufficient affinity to target MerTK. refers to antibodies useful as diagnostic and/or therapeutic agents. In one embodiment, the extent to which the anti-MerTK antibody binds to an unrelated non-MerTK polypeptide is less than about 10% of the antibody's binding to MerTK, eg, as measured by radioimmunoassay (RIA). In certain embodiments, antibodies that bind MerTK have a dissociation constant (KD) <1 μM, <100 nM, <10 nM, <1 nM, <0.1 nM, <0.01 nM, or <0.001 nM (e.g., 10 ⁻⁸ M or less, such as from 10 ⁻⁸ M to 10 ⁻¹³ M, such as from 10 ⁻⁹ M to 10 ⁻¹³ M). In certain embodiments, the anti-MerTK antibody binds to an epitope of MerTK that is conserved among MerTKs from different species.

With respect to binding of an antibody to a target molecule, the terms "specific binding" or "specifically binds" or "is specific" for a particular polypeptide or epitope of a particular polypeptide target refer to non-specific mutual Action means a distinctly different binding. Specific binding can be measured, for example, by determining binding of a molecule relative to binding of a control molecule. For example, specific binding can be determined by competition with a control molecule similar to the target, eg, excess unlabeled target. In this case, specific binding is indicated when binding of the labeled target to the probe is competitively inhibited by excess unlabeled target. As used herein, the term “specific binding” or “specifically binds” or “is specific” for a particular polypeptide or epitope of a particular polypeptide target means, for example, 10 ⁻⁴ M or less, 10 ⁻⁵ M or less, 10 ⁻⁶ M or less, 10 ⁻⁷ M or less, 10 ⁻⁸ M or less, 10 ⁻⁹ M or less, 10 ⁻¹⁰ M or less, 10 ^{− 11} M or less, 10 ⁻¹² M or less, or with a KD in the range of 10 ⁻⁴ M to 10 ⁻⁶ M or 10 ⁻⁶ M to 10 ⁻¹⁰ M or 10 ⁻⁷ M to 10 ⁻⁹ M can be shown. As will be appreciated by those skilled in the art, affinity and KD values are inversely related. A high affinity for an antigen is measured by a low KD value. In one embodiment, the term "specific binding" refers to the binding of a molecule to a particular polypeptide or epitope of a particular polypeptide without substantial binding to any other polypeptide or polypeptide epitope. refers to a bond that

The term "immunoglobulin" (Ig) is used herein synonymously with "antibody." The term "antibody" herein is used in the broadest sense, in particular monoclonal antibodies, polyclonal antibodies, multispecific antibodies (e.g. bispecific antibodies) including those formed from at least two intact antibodies. antibodies), and antibody fragments that bind antigen so long as they exhibit the desired biological activity.

"Native antibodies" are usually heterotetrameric glycoproteins of about 150,000 daltons, composed of two identical light ("L") chains and two identical heavy ("H") chains. . Each light chain is linked to a heavy chain by one covalent disulfide bond, although the number of disulfide bonds varies with the heavy chain of the immunoglobulin isotype. Each heavy and light chain also has regularly spaced intrachain disulfide bridges. Each heavy chain has at one end a variable domain (V _H ) followed by a number of constant domains. Each light chain has a variable domain at one end (V _L ) and a constant domain at its other end; the light chain constant domain is aligned with the first constant domain of the heavy chain; aligns with the variable domain of the heavy chain. Particular amino acid residues are believed to form an interface between the light and heavy chain variable domains.

For the structure and properties of different antibody classes see, eg, Basic and Clinical Immunology, 8th Ed. , Daniel P.; Stites, Abba I.; Terr and TristramG. See Parslow (eds.), Appleton & Lange, Norwalk, Conn., 1994, page 71 and Chapter 6.

Light chains from any vertebrate species are of one of two distinct types, called kappa (“κ”) and lambda (“λ”), based on the amino acid sequences of their constant domains. can be assigned. Depending on the amino acid sequences of the constant domain (CH) of their heavy chains, immunoglobulins can be assigned to different classes or isotypes. There are five classes of immunoglobulins: IgA, IgD, IgE, IgG, and IgM, respectively alpha (“α”), delta (“δ”), epsilon (“ε”), gamma (“γ”), and a heavy chain denoted as mu (“μ”). The gamma and alpha classes are further divided into subclasses (isotypes) based on relatively minor differences in CH sequence and function, for example humans have the following subclasses: IgG1, IgG2, IgG3, IgG4, IgA1, and IgA2. Express. The subunit structures and three-dimensional configurations of different immunoglobulin classes are well known, see, for example, Abbas et al. , Cellular and Molecular Immunology, ^4th ed. (WB Saunders Co., 2000).

A "variable region" or "variable domain" of an antibody, eg, an anti-MerTK antibody of this disclosure, refers to the amino-terminal domain of the heavy or light chain of the antibody. The heavy and light chain variable domains may be referred to as "V _H " and "V _L ", respectively. These domains are generally the most variable parts of the antibody (relative to other antibodies of the same class) and contain the antigen binding sites.

The term "variable" refers to the fact that certain segments of the variable domains differ extensively in sequence between antibodies, eg, the anti-MerTK antibodies of this disclosure. The variable domains mediate antigen binding and define the specificity of a particular antibody for its particular antigen. However, the variability is not evenly distributed throughout the variable domains. Instead, it is concentrated in three segments called hypervariable regions (HVRs) in both the light and heavy chain variable domains. The more highly conserved portions of variable domains are called the framework regions (FR). The variable domains of naturally occurring heavy and light chains each contain four FR regions that adopt a predominantly beta-sheet configuration connected by three HVRs, which connect the beta-sheet structures; It forms a loop, which in some cases forms part of it. The HVRs in each chain are held together in close proximity by the FR regions and, together with the HVRs from the other chain, contribute to the formation of the antibody's antigen-binding site (Kabat et al., Sequences of Immunological Interest, Fifth Edition, National Institute of Health, Bethesda, Md. (1991)). The constant domains are not directly involved in binding an antibody to an antigen, but exhibit various effector functions, such as involvement in antibody-dependent cellular cytotoxicity.

As used herein, the term "monoclonal antibody" refers to a population of substantially homogeneous antibodies, i.e., a potentially naturally occurring antibody in which the individual antibodies that make up the population may be present in minute amounts. Refers to antibodies obtained from populations that are identical except for mutations and/or post-translational modifications (eg, isomerization, amidation, etc.), eg, monoclonal anti-MerTK antibodies of the present disclosure. Monoclonal antibodies are highly specific against a single antigenic site. In contrast to polyclonal antibody preparations which typically include different antibodies directed against different determinants (epitopes), each monoclonal antibody is directed against a single determinant on the antigen. In addition to their specificity, monoclonal antibodies are advantageous in that they are synthesized by hybridoma cultures uncontaminated by other immunoglobulins. The modifier "monoclonal" indicates the character of the antibody as being obtained from a substantially homogeneous population of antibodies and is not to be construed as requiring production of the antibody by any particular method. For example, monoclonal antibodies used in accordance with the present invention can be isolated from one or more DNA(s) in the following manner: from animals including, but not limited to, rats, mice, rabbits, guinea pigs, hamsters and/or chickens. ), virus-like particle, polypeptide(s), and/or cell(s) immunization, hybridoma technology, B cell cloning technology, recombinant DNA technology, and part or all of the human immunoglobulin locus or human They can be produced by a variety of techniques including, but not limited to, one or more of those that produce human or human-like antibodies in animals having genes encoding immunoglobulin sequences.

The terms "full-length antibody", "intact antibody" or "whole antibody" are used interchangeably and, in contrast to antibody fragments, antibodies in their substantially intact form, e.g. Refers to the MerTK antibody. Specifically, whole antibodies include those having heavy and light chains, including the Fc region. The constant domains may be native sequence constant domains (eg, human native sequence constant domains) or amino acid sequence variants thereof. In some cases, the intact antibody may have one or more effector functions.

"Antibody fragment" refers to a molecule other than an intact antibody that contains a portion of the intact antibody that binds to the antigen to which the intact antibody binds. Examples of antibody fragments include Fab, Fab', F(ab') ₂ and Fv fragments, diabodies, linear antibodies (US Pat. No. 5,641,870, Example 2, Zapata et al., Protein Eng. 8 (10 ): 1057-1062 (1995)), single-chain antibody molecules and multispecific antibodies formed from antibody fragments.

Papain digestion of an antibody, such as an anti-MerTK antibody of the present disclosure, produces two identical antigen-binding fragments, called "Fab" fragments, and a residual "Fc" fragment whose name reflects its ability to readily crystallize. be done. A Fab fragment consists of all the light and heavy chain variable region domains (V _H ) and the first constant domain of one heavy chain (C _H 1). Each Fab fragment is monovalent with respect to antigen binding, ie, has a single antigen binding site. Pepsin treatment of the antibody yields a single large F(ab') ₂ fragment, which roughly corresponds to two disulfide-linked Fab fragments with different antigen-binding activities, still capable of cross-linking antigen. is possible. Fab' fragments differ from Fab fragments by having a few additional residues at the carboxy terminus of the C _H 1 domain including one or more cysteines from the antibody hinge region. Fab'-SH is the designation herein for Fab' in which the constant domain cysteine residue(s) bear a free thiol group. F(ab') ₂ antibody fragments originally were produced as pairs of Fab' fragments which have hinge cysteines between them. Other chemical couplings of antibody fragments are also known.

The Fc fragment contains the carboxy-terminal portions of both heavy chains held together by a disulfide. The effector functions of antibodies are determined by sequences in the Fc region, which region is also recognized by Fc receptors (FcR) found on certain cell types.

A "functional fragment" of an antibody, e.g., an anti-MerTK antibody of the present disclosure, comprises a portion of an intact antibody, generally retaining or modifying the antigen-binding or variable region of the intact antibody, or FcR binding ability. includes the Fc region of an antibody with a modified FcR binding capability. Examples of antibody fragments include linear antibodies, single chain antibody molecules and multispecific antibodies formed from antibody fragments.

The term "diabody" refers to the combination of VH domains and _VH domains to achieve interchain, but not intrachain, pairing of the variable domains, thereby resulting in a bivalent fragment, ie, a fragment with two antigen-binding sites. Refers to small antibody fragments prepared by constructing sFv fragments (see previous paragraph) with short linkers (about 5-10 residues) between the _VL domains. Bispecific diabodies are heterodimers of two "crossed" sFv fragments in which the _VH and _VL domains of the two antibodies are present on different polypeptide chains.

As used herein, a "chimeric antibody" is one in which a portion of the heavy and/or light chain is identical to the corresponding sequences of an antibody derived from a particular species or belonging to a particular antibody class or subclass. or homologous, while the remainder of said chain(s) is identical or homologous to the corresponding sequence of an antibody from another species or belonging to another antibody class or subclass (immunoglobulin), e.g. , refers to chimeric anti-MerTK antibodies of the present disclosure, as well as fragments of such antibodies so long as they exhibit the desired biological activity. Chimeric antibodies of interest herein include PRIMATIZED® antibodies in which the antigen binding region of the antibody is derived from an antibody produced by, for example, immunizing macaque monkeys with the antigen of interest. As used herein, "humanized antibody" is used as a subset of "chimeric antibody."

Humanized forms of non-human (eg, murine) antibodies, eg, humanized forms of the anti-MerTK antibodies of this disclosure, are chimeric antibodies comprising amino acid residues from non-human HVRs and human FRs. In certain embodiments, a humanized antibody comprises substantially all of at least one, usually two, variable domains and all or substantially all of the HVRs (e.g., CDRs) are those of a non-human antibody. and all or substantially all of the FRs correspond to those of a human antibody. A humanized antibody optionally can comprise at least a portion of an antibody constant region derived from a human antibody. A “humanized form” of an antibody, eg, a non-human antibody, refers to an antibody that has undergone humanization.

A "human antibody" refers to an antibody produced by a human, e.g., an antibody having an amino acid sequence corresponding to that of an anti-MerTK antibody of this disclosure, and/or of the techniques for making human antibodies disclosed herein. is an antibody made using any of This definition of human antibody specifically excludes humanized antibodies that contain non-human antigen-binding residues. Human antibodies can be produced using various techniques known in the art, including phage display libraries and yeast display libraries. Human antibodies are modified to produce such antibodies in response to antigenic challenge, but by administering the antigen to a transgenic animal in which its endogenous locus has been disabled, e.g., an immunized XenoMouse. It may be prepared or produced with human B-cell hybridoma technology.

As used herein, the term "hypervariable region", "HVR" or "HV" refers to antibody variable regions that are hypervariable in sequence and/or form structurally defined loops. A region of a domain, eg, a region of an antibody variable domain of an anti-MerTK antibody of the present disclosure. In general, an antibody contains 6 HVRs, 3 in _{the VH} (H1, H2, H3) and 3 in _{the VL} (L1, L2, L3). In native antibodies, H3 and L3 exhibit the most diversity of the six HVRs, with H3 in particular thought to play a unique role in conferring fine specificity to antibodies. Camelid antibodies consisting of only naturally occurring heavy chains are functional and stable in the absence of light chains.

Several HVR depictions are used herein and are included herein. In some embodiments, the HVRs may be Kabat Complementarity Determining Regions (CDRs) based on sequence variability, which are the most commonly used (Kabat et al., supra). In some embodiments, the HVR may be a Clothia CDR. Chothia refers instead to the location of structural loops (Chothia and Lesk J. Mol. Biol. 196:901-917 (1987)). In some embodiments, the HVR may be an AbM HVR. The AbM HVR represents a compromise between the Kabat CDRs and the Chothia structural loops and is used by Oxford Molecular's AbM antibody modeling software. In some embodiments, the HVR may be a "contact" HVR. The "contact" HVR is based on analysis of available complex crystal structures. The residues for each of these HVRs are shown below.

HVRs may include the following "extended HVRs": 24-36 or 24-34 (L1), 46-56 or 50-56 (L2) and 89-97 or 89-96 (L3) in the VL, and 26-35 (H1), 50-65 or 49-65 (preferred embodiments) (H2), and 93-102, 94-102 or 95-102 (H3) in VH. The variable domain residues are identified in Kabat et al. for each of these extended HVR definitions. (cited above).

"Framework" or "FR" residues are those variable domain residues other than the HVR residues as herein defined.

As used herein, an "acceptor human framework _" is a framework that comprises a VL or _VH framework amino acid sequence derived from a human immunoglobulin framework or a human consensus framework. An acceptor human framework “derived from” a human immunoglobulin framework or a human consensus framework may contain the same amino acid sequence or may contain changes in an existing amino acid sequence. In some embodiments, the number of existing amino acid changes is 10 or less, 9 or less, 8 or less, 7 or less, 6 or less, 5 or less, 4 or less, 3 or less, or 2 less than or equal to If existing amino acid changes are present in VH, preferably if those changes are only at 3, 2 or 1 of positions 71H, 73H and 78H, e.g. The residues can be 71A, 73T, and/or 78A. In one embodiment, the VL acceptor human framework is identical in sequence to a _VL human immunoglobulin framework sequence or a human consensus framework sequence.

A "human consensus framework" is a framework that represents the most commonly occurring amino acid residues in a selection of human immunoglobulin _VL or _VH framework sequences. Generally, the selection of human immunoglobulin _VL or _VH sequences is made from a subgroup of variable domain sequences. In general, subgroups of sequences are described in Kabat et al. , Sequences of Proteins of Immunological Interest, 5th Ed. Subgroups as in Public Health Service, National Institutes of Health, Bethesda, Md. (1991). Taken as an example for _VL , the subgroup is defined by Kabat et al. (supra) may be subgroup kappa I, kappa II, kappa III or kappa IV. In addition, for _VH , the subgroups are as described in Kabat et al. It may be subgroup I, subgroup II, or subgroup III as in (supra).

For example, an "amino acid modification" at a particular position in the anti-MerTK antibodies of this disclosure refers to the substitution or deletion of a particular residue, or insertion of at least one amino acid residue adjacent to the particular residue. An insertion "flanking" a particular residue means an insertion within 1-2 residues of that residue. The insertion may be N-terminal or C-terminal to the specified residue. Preferred amino acid modifications herein are substitutions.

"Fv" is the minimum antibody fragment which contains a complete antigen-recognition and -binding site. This fragment consists of a dimer of one heavy and one light chain variable region domain in tight, non-covalent association. Folding of these two domains results in six hypervariable loops (three loops each from the H and L chains) that provide the amino acid residues for antigen binding and give the antibody its antigen-binding specificity. give. However, even a single variable domain (or half Fv containing only 3 antigen-specific HVRs) has the ability to recognize and bind antigen, albeit with lower affinity than the entire binding site. have.

"Single-chain Fv" sometimes abbreviated as "sFv" or "scFv" are antibody fragments that comprise the VH and VL antibody domains connected into a single polypeptide chain. Preferably, the sFv polypeptide further comprises a polypeptide linker between the _VH and _VL domains, which allows the sFv to form the desired structure for antigen binding.

Antibody "effector functions" refer to those biological activities attributable to the Fc region (a native sequence Fc region or amino acid sequence variant Fc region) of an antibody, and vary with the antibody isotype.

The term "Fc region" herein is used to define a C-terminal region of an immunoglobulin heavy chain, and includes native sequence Fc regions and variant Fc regions. Although the boundaries of the Fc region of an immunoglobulin heavy chain can vary, the human IgG heavy chain Fc region is usually defined as extending from amino acid residue position Cys226, or Pro230, to its carboxyl terminus. The C-terminal lysine of the Fc region (residue 447 according to the EU numbering system) can be removed, for example, during production or purification of the antibody, or by recombinant manipulation of the nucleic acid encoding the heavy chain of the antibody. Thus, the composition of an intact antibody includes an antibody population with all K447 residues removed, an antibody population with no K447 residues removed, and antibodies with a mixture of antibodies with and without the K447 residue. It can contain populations. Suitable native sequence Fc regions for use in the antibodies of the present disclosure include human IgG1, IgG2, IgG3 and IgG4.

A "native sequence Fc region" comprises an amino acid sequence identical to the amino acid sequence of an Fc region found in nature. Native sequence human Fc regions include native sequence human IgGl Fc regions (non-A and A allotypes), native sequence human IgG2 Fc regions, native sequence human IgG3 Fc regions, and native sequence human IgG4 Fc regions, and Included are naturally occurring variants thereof.

A "variant Fc region" comprises an amino acid sequence that differs from that of a native sequence Fc region by virtue of at least one amino acid modification, preferably one or more amino acid substitutions. Preferably, said variant Fc region has at least one amino acid substitution in the native sequence Fc region or in the Fc region of the parent polypeptide compared to the native sequence Fc region or the Fc region of the parent polypeptide, e.g. It has from to about 10 amino acid substitutions, and preferably from about 1 to about 5 amino acid substitutions. Variant Fc regions herein are preferably at least 80% homologous, most preferably at least 90% homologous, more preferably at least 90% homologous to the native sequence Fc region and/or the Fc region of the parent polypeptide. , have at least 95% homology with them.

"Fc receptor" or "FcR" refers to a receptor that binds to the Fc region of an antibody. A preferred FcR is a native sequence human FcR. Further, preferred FcRs are those that bind IgG antibodies (gamma receptors) and include receptors of the FcγRI, FcγRII, and FcγRIII subclasses, i. FcγRII receptors include FcγRIIA (an “activating receptor”) and FcγRIIB (an “inhibiting receptor”), which share similar amino acid sequences that differ primarily in their cytoplasmic domains. have. Activating receptor FcγRIIA contains an immunoreceptor tyrosine-based activation motif (“ITAM”) in its cytoplasmic domain. Inhibitory receptor FcγRIIB contains an immunoreceptor inhibitory tyrosine motif (“ITIM”) in its cytoplasmic domain. Other FcRs, including those to be identified in the future, are encompassed by the term "FcR" herein. FcRs can also increase the serum half-life of antibodies.

As used herein, "percent (%) amino acid sequence identity" and "homology" with respect to a peptide, polypeptide or antibody sequence means that the sequences are aligned for maximum percent sequence identity, Refers to the percentage of amino acid residues in a candidate sequence that are identical to amino acid residues in a specified peptide or polypeptide sequence, after the introduction of gaps where necessary, and does not consider conservative substitutions as part of the sequence identity . Alignments to determine percent amino acid sequence identity are published by a variety of methods within the skill of those in the art, such as BLAST, BLAST-2, ALIGN or MEGALIGN™ (DNASTAR) software. It can be accomplished using computer software. Those skilled in the art can determine appropriate parameters for evaluating alignment, including any algorithms known in the art required to achieve maximal alignment over the full length of the sequences being compared. can.

The term "competing" when used in the context of antibodies competing for the same or overlapping epitopes means that the antibody being tested is directed against a common antigen (e.g. MerTK or fragment thereof) by a reference molecule (e.g. ligand, or reference antibody), competition between antibodies as determined by an assay that prevents or inhibits (eg, reduces) specific binding. Competitive binding assays of many types, such as solid phase direct or indirect radioimmunoassay (RIA), solid phase direct or indirect enzyme immunoassay (EIA), sandwich competition assays (e.g. Stahli et al., 1983, Methods in Enzymology 9:242-253), solid phase direct biotin-avidin EIA (see, for example, Kirkland et al., 1986, J. Immunol. 137:3614-3619), solid phase direct labeling assay, solid phase direct labeling sandwich assay. (See, e.g., Harlow and Lane, 1988, Antibodies, A Laboratory Manual, Cold Spring Harbor Press), solid phase direct labeling RIA using I-125 label (e.g., Morel et al., 1988, Molec. Immunol. 25: 7-15), solid-phase direct biotin-avidin EIA (see, for example, Cheung, et al., 1990, Virology 176:546-552), and direct labeling RIA (Moldenhauer et al., 1990, Scand. J. Immunol). .32:77-82) can be used to determine whether an antibody competes with another antibody. Typically, such assays involve the use of purified antigen bound to a solid surface or cells with either unlabeled test antibody and labeled reference antibody. Competitive inhibition is measured by determining the amount of label bound to the solid surface or cells in the presence of the test antibody. Test antibodies are usually present in excess. Antibodies identified by a competition assay (competing antibodies) include antibodies that bind to the same epitope as the reference antibody, and those that are sufficiently proximal to the epitope to which the reference antibody binds to cause steric hindrance. Antibodies that bind to epitopes on Usually, when a competing antibody is present in excess, it reduces specific binding of a reference antibody to a common antigen by at least 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%. , 90%, 95%, 97.5%, and/or nearly 100% inhibition (eg, reduction).

As used herein, an "interaction" between a MerTK polypeptide and a second polypeptide includes, but is not limited to protein-protein interactions, physical interactions, chemical interactions, It includes bonding, covalent bonding, and ionic bonding. As used herein, an antibody "inhibits an interaction" between two polypeptides when the antibody disrupts, reduces or completely eliminates the interaction between the two polypeptides. When an antibody of this disclosure binds to one of two polypeptides, it "inhibits the interaction" between the two polypeptides. In some embodiments, the interaction is at least 20%, 30%, 40%, 50%, 60%, 70%, 80%, 85%, 90%, 95%, 97.5% and/or or nearly 100% can be either inhibited.

The term "epitope" includes any determinant capable of being bound by an antibody. An epitope is a region of an antigen that is bound by an antibody that targets it, and includes specific amino acids that, when the antigen is a polypeptide, directly contact the antibody. Most often epitopes are present on polypeptides, but in some cases they may be present on other types of molecules such as nucleic acids. Epitopic determinants can include chemically active surface groupings of molecules such as amino acids, sugar side chains, phosphoryl or sulfonyl groups, and can have specific three dimensional structural characteristics, and/or specific charge characteristics. . In general, antibodies specific for a particular target antigen preferentially recognize epitopes of the target antigen in a complex mixture of polypeptides and/or macromolecules.

An "isolated" antibody, e.g., an isolated anti-MerTK antibody of the present disclosure, is one that has been identified, separated and/or recovered from a component of its production environment (e.g., natural or recombinant). Preferably, the isolated antibody is free of association with all other contaminant components from its production environment. Contaminant components from its production environment, for example those originating from recombinantly transfected cells, are substances that would normally interfere with the research, diagnostic or therapeutic use of the antibody and include enzymes, hormones, and other proteinaceous or non-proteinaceous solutes. In preferred embodiments, the antibody comprises (1) greater than 95%, in some embodiments, greater than 99% by weight of the antibody, e.g., as measured by the Lowry method; to an extent sufficient to obtain at least 15 N-terminal or internal amino acid sequence residues, or (3) under non-reducing or reducing conditions using Coomassie blue staining or preferably silver staining. Purified to homogeneity by SDS-PAGE. Isolated antibody includes the antibody in situ within recombinant T cells since at least one component of the antibody's natural environment will not be present. Ordinarily, however, isolated polypeptide or antibody will be prepared by at least one purification step.

An "isolated" nucleic acid molecule encoding an antibody, e.g., an anti-MerTK antibody of the disclosure, is a nucleic acid that is identified and separated from at least one contaminant nucleic acid molecule with which it is ordinarily associated in the environment in which it is produced. is a molecule. Preferably, the isolated nucleic acid is free of association with all components associated with the production environment. An isolated nucleic acid molecule encoding a polypeptide and antibody herein is in a form other than in the form or setting in which it is found in nature. Isolated nucleic acid molecules therefore are distinguished from nucleic acids encoding the polypeptides and antibodies herein as they exist naturally in cells.

As used herein, the term "vector" is intended to refer to a nucleic acid molecule capable of transporting another nucleic acid to which it has been linked. One type of vector is a "plasmid," which refers to a circular double-stranded DNA into which additional DNA segments can be ligated. Another type of vector is a phage vector. Another type of vector is a viral vector, wherein additional DNA segments can be ligated into the viral genome. Certain vectors are capable of autonomous replication in a host cell into which they are introduced (eg, bacterial vectors having a bacterial origin of replication and episomal mammalian vectors). Other vectors, such as non-episomal mammalian vectors, can be integrated into the genome of the host cell upon introduction into the host cell and are thus replicated along with the host genome. Moreover, certain vectors are capable of directing the expression of genes to which they are operably linked. Such vectors are referred to herein as "recombinant expression vectors," or simply "expression vectors." In general, expression vectors of utility in recombinant DNA technology are often in the form of plasmids. In the present specification, "plasmid" and "vector" are used interchangeably as the plasmid is the most commonly used form of vector.

"Polynucleotide," or "nucleic acid," as used interchangeably herein, refer to polymers of nucleotides of any length, and include DNA and RNA. The nucleotides can be deoxyribonucleotides, ribonucleotides, modified nucleotides or bases, and/or analogues thereof, or any substrate that can be incorporated into a polymer by a DNA or RNA polymerase or by a synthetic reaction.

A "host cell" includes an individual cell or cell culture that can be or has been a recipient for vector(s) for incorporation of polynucleotide inserts. A host cell includes the progeny of a single host cell, which progeny may not necessarily be completely identical to the original parent cell, due to natural, accidental, or deliberate mutation ( in morphology or genomic DNA complement). Host cells include cells transfected in vivo with the polynucleotide(s) of the invention.

As used herein, "carrier" includes a pharmaceutically acceptable carrier, excipient or stabilizer that is non-toxic to cells or mammals to which it is exposed at the dosages and concentrations employed. drug is included.

As used herein, the term "treatment" refers to clinical intervention designed to alter the natural course of the treated individual during the course of clinical pathology. Desirable therapeutic effects include slowing the rate of progression of the particular disease, disorder, or condition, ameliorating or alleviating the morbidity, and remission or improving prognosis. For example, an individual is successfully "treated" if one or more symptoms associated with a particular disease, disorder, or condition are reduced or eliminated.

An "effective amount" refers to the lowest amount effective, at dosages and for periods of time necessary to achieve the desired therapeutic result. An effective amount may be provided in one or more administrations. An effective amount is also one in which any toxic or detrimental effects of the treatment are outweighed by the therapeutically beneficial effects. For therapeutic use, beneficial or desired results include reduction in one or more symptoms attributable to the disease, improvement in quality of life for those affected by the disease, reduction in doses of other drugs needed to treat the disease. Clinical outcomes such as reduction, enhancement of the effect of another drug, eg, through targeting, delaying disease progression, and/or prolonging survival are included. An effective amount of a drug, compound, or pharmaceutical composition is that amount sufficient to achieve therapeutic treatment, either directly or indirectly. As understood in the clinical setting, an effective amount of a drug, compound or pharmaceutical composition may or may not be achieved in conjunction with another drug, compound or pharmaceutical composition. Thus, an "effective amount" may be viewed in the context of administration of one or more therapeutic agents, whether a single agent in combination with one or more other agents can achieve the desired result, or if achieved, can be considered to be administered in an effective amount.

"Individual" for purposes of therapy includes humans, domestic and farm animals, as well as zoo, sporting or pet animals such as dogs, horses, rabbits, cows, pigs, hamsters, gerbils, mice, ferrets, rats, cats. Any animal classified as a mammal, including In some embodiments, the individual is human.

As used herein, "concurrent" administration with another compound or composition includes simultaneous administration and/or administration at different times. Co-administration also encompasses administration as a combination or administration as separate compositions, including at different dosing frequencies or intervals and using the same or different routes of administration. In some embodiments, co-administration is administration as part of the same therapeutic regimen.

As used herein, the term "about" refers to the normal error range for the respective value readily understood by those skilled in the art. Reference to “about” a value or parameter herein includes (and describes) embodiments that are directed to that value or parameter per se.

As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. For example, reference to an "antibody" is a reference to one to many antibodies, such as in molar amounts, including equivalents thereof known to those skilled in the art, and so on.

Aspects and embodiments of the disclosure described herein may include “including” aspects and embodiments, “consisting of” aspects and embodiments, and “consisting essentially of” aspects and embodiments. understood.

I. Anti-MerTK Antibodies Provided herein are anti-MerTK antibodies. Antibodies provided herein are useful, for example, in diagnosing or treating MerTK-related disorders.

In one aspect, the disclosure provides an isolated (eg, monoclonal) antibody that binds to an epitope within a MerTK protein or polypeptide of the disclosure. MerTK proteins or polypeptides of the present disclosure include mammalian MerTK proteins or polypeptides, human MerTK proteins or polypeptides, mouse (murine) MerTK proteins or polypeptides, and cynomolgus monkey MerTK proteins or polypeptides. It is not limited to these. MerTK proteins and polypeptides of the disclosure include naturally occurring variants of MerTK. In some embodiments, the MerTK proteins and polypeptides of this disclosure are membrane bound. In some embodiments, the MerTK proteins and polypeptides of this disclosure are the soluble extracellular domain of MerTK.

In some embodiments, MerTK is expressed in cells. In some embodiments, MerTK is expressed in phagocytic cells, including but not limited to macrophages and dendritic cells. In some embodiments, MerTK is expressed on monocytes, natural killer cells, natural killer T cells, microglia, endothelial cells, megakaryocytes, and platelets. In some embodiments, high levels of MerTK expression are also found in ovary, prostate, testis, lung, retina, and kidney. Moreover, MerTK is ectopic or overexpressed in many cancers (Linger et al, 2008, Adv Cancer Res, 100:35-83).

Antibody Activity In some embodiments, anti-MerTK antibodies are provided that bind to human MerTK but not to cynomolgus monkey MerTK. In some embodiments, anti-MerTK antibodies are provided that bind to human MerTK, but not to mouse MerTK. In some embodiments, anti-MerTK antibodies are provided that bind to human MerTK, but not to cynomolgus monkey MerTK, and not to mouse MerTK. In some embodiments, an anti-MerTK antibody that binds to human MerTK and binds to cynomolgus monkey MerTK is provided. In some embodiments, an anti-MerTK antibody is provided that binds human MerTK, binds cynomolgus monkey MerTK, but does not bind mouse MerTK. In some embodiments, anti-MerTK antibodies that bind human MerTK and that bind mouse MerTK are provided. In some embodiments, an anti-MerTK antibody is provided that binds human MerTK, binds mouse MerTK, but does not bind cynomolgus monkey MerTK. In some embodiments, anti-MerTK antibodies that bind human MerTK, cynomolgus monkey MerTK, and mouse MerTK are provided. Anti-MerTk antibodies that bind to human, cynomolgus monkey, and mouse MerTK are convenient for in vivo testing in mammalian disease (eg, cancer) models and testing in non-human primates.

MerTK Binding Partners MerTK proteins of the disclosure include, but are not limited to, protein S (ProS or ProS1), growth arrest specific gene 6 (Gas6), tabby, tabby-like protein 1 (TULP-1), and galectin-3. Interacts (eg, binds) with one or more ligands or binding partners without limitation. Anti-MerTK antibodies of the present disclosure can affect the interaction of MerTK with one or more of its various ligands and binding partners.

Anti-MerTK antibodies of the present disclosure were identified that blocked both ProS and Gas6 binding to MerTK, blocked only ProS binding to MerTK, or blocked neither ProS nor Gas6 binding to MerTK. An anti-MerTK antibody that blocks only ProS did not bin with the ProS/Gas6 double-blocking anti-MerTK antibody (as shown in the Examples below), indicating that non-MerTK antibodies to these two classes of anti-MerTK antibodies identified herein did not bin together. Overlapping epitopes were suggested.

Accordingly, in some embodiments, anti-MerTK antibodies of the present disclosure inhibit (ie, block) or reduce binding between MerTK and one or more MerTK ligands. In some embodiments, an anti-MerTK antibody of the disclosure inhibits or reduces binding of ProS to MerTK. In some embodiments, an anti-MerTK antibody of the disclosure inhibits or reduces binding of ProS to MerTK, but does not inhibit or reduce binding of Gas6 to MerTK. In some embodiments, anti-MerTK antibodies of the present disclosure inhibit or reduce binding of Gas6 to MerTK. In some embodiments, an anti-MerTK antibody of the disclosure inhibits or reduces binding of Gas6 to MerTK, but does not inhibit or reduce binding of ProS to MerTK. In yet other embodiments, the anti-MerTK antibodies of the disclosure inhibit or reduce binding of ProS to MerTK and inhibit or reduce binding of Gas6 to MerTK. In other embodiments, the anti-MerTK antibodies of the disclosure do not inhibit or reduce binding of ProS to MerTK and do not inhibit or reduce binding of Gas6 to MerTK.

IC50 values for inhibiting or blocking Gas6 ligand binding to MerTK or for inhibiting or blocking ProS ligand binding to MerTK are known to those of skill in the art, such as those described herein in the Examples below (e.g., Example 13). can be identified using the method of In some embodiments, an anti-MerTK antibody of the disclosure inhibits or reduces Gas6 ligand binding or inhibits or reduces ProS ligand binding to MerTK in vitro. In some embodiments, an anti-MerTK antibody of the disclosure inhibits or reduces Gas6 ligand binding to human MerTK with an IC50 value in the range of 0.29 nM to 32 nM. In some embodiments, the anti-MerTK antibodies of the present disclosure exhibit Gas6 ligand binding to human MerTK with IC50 values ranging from 0.29 nM to 1.0 nM, ranging from 1.0 nM to 5 nM, ranging from 5 nM to 10 nM, 10 nM. ~25 nM, or a range of 25 nM to 32 nM to inhibit or reduce. In some embodiments, an anti-MerTK antibody of the disclosure inhibits or reduces ProS ligand binding to human MerTK with an IC50 value in the range of 0.58 nM to 25.9 nM. In some embodiments, the anti-MerTK antibodies of the present disclosure exhibit ProS ligand binding to human MerTK with IC50 values in the range of 0.58 nM to 1 nM, 1 nM to 2.5 nM, 2.5 nM to 5 nM, 5 nM. ~10 nM, 10 nM to 25 nM range of inhibition or reduction.

The relative effectiveness of antibodies in reducing or inhibiting ProS and Gas6 binding to MerTK can be determined using such IC50 values. For example, an antibody that inhibits the binding of Gas6 to MerTK with an IC50 value that is 1.7-fold higher than the IC50 value for inhibition of ProS binding to MerTK showed a 1.7 times more effective in reducing or inhibiting the binding of In some embodiments, the anti-MerTK antibody reduces or inhibits binding of ProS to MerTK by at least 1.7-fold, at least 2.3-fold, at least 2-fold, than in reducing or inhibiting binding of Gas6 to MerTK. .4 times, at least 5 times, at least 7.7 times, or at least 8.5 times more effective.

In some embodiments, an anti-MerTK antibody of this disclosure reduces Gas6 ligand binding to MerTK by at least 20%, at least 25%, compared to Gas6 ligand binding to MerTK in the absence of an anti-MerTK antibody of this disclosure. , at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95% inhibition or reduction. In some embodiments, an anti-MerTK antibody of this disclosure reduces ProS ligand binding to MerTK by at least 20%, at least 25%, compared to ProS ligand binding to MerTK in the absence of an anti-MerTK antibody of this disclosure. %, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95% inhibition or reduction. The percent inhibition or reduction of Gas6 ligand binding to MerTK or the percent inhibition or reduction of ProS ligand binding to MerTK can be determined using standard methods known to those of skill in the art, such as those described herein in Example 13. , can be identified by measuring IC50 values.

Further provided herein are methods of screening for anti-MerTK antibodies that bind to MerTK and block or reduce interaction of MerTK with one or more MerTK ligands or binding partners.

pAKT
AKT activity is a downstream target of Gas6 binding to MerTK, Axl, or Tyro-3 receptors. For example, binding of the MerTK ligand Gas6 to MerTK induces phosphorylation of AKT (pAKT) (eg, Angelillo-Scherrer et al, 2008, J Clin Invest, 118:583-596, Moody et al, 2016, Int J Cancer, 139:1340-1349). Anti-MerTK antibodies of the present disclosure were effective in inhibiting Gas6-mediated phosphorylated AKT (pAKT) activity in human macrophages (eg, M2c macrophages) in a dose-dependent manner. Thus, the anti-MerTK antibodies of the disclosure were effective in inhibiting Gas6-mediated MerTK signaling, as evidenced by inhibition of pAKT levels. In some embodiments, an anti-MerTK antibody of the disclosure inhibits or reduces Gas6-mediated pAKT activity in vitro.

The relative efficacy of anti-MerTK antibodies in reducing or inhibiting pAKT activity in cells can be determined by measuring the IC50 values. IC50 values for Gas6-mediated inhibition of pAKT activity can be determined using methods known to those skilled in the art, such as those described herein in Example 22 below. In some embodiments, anti-MerTK antibodies of the present disclosure inhibit Gas6-mediated pAKT activity in macrophages (eg, M2c macrophages) with IC50 values ranging from 0.019 nM to 7.74 nM. In some embodiments, the anti-MerTK antibodies of the present disclosure inhibit Gas6-mediated pAKT activity in macrophages (eg, M2c macrophages) with IC50 values of 0.019 nM-0.25 nM, 0.25 nM-0.50 nM, 0 .50 nM to 1.0 nM, 1.0 nM to 2.5 nM, 2.5 nM to 5.0 nM, or 5.0 nM to 10 nM.

Efferocytosis Efferocytosis refers to the phagocytic clearance of dying or apoptotic cells. Efferocytosis can be accomplished by professional phagocytes (e.g., macrophages, dendritic cells, microglia), non-professional phagocytes (e.g., epithelial cells, fibroblasts, retinal pigment epithelial cells), or specialized phagocytes. (Elliott et al, 2017, J Immunol, 198:1387-1394). Efferocytosis results in the removal of dead or dying cells before their membrane integrity has been disrupted and their cellular contents leaked into the surrounding tissue, thus allowing the tissue to react with toxic enzymes, oxidants, and oxidants. agents, and other intracellular components.

Apoptotic cells expose a variety of molecules on the cell surface that are recognized by phagocytic receptors (“eat-me” signals). One such "eat me" signaling molecule is phosphatidylserine (PtdSer), which normally resides in the inner leaflet of the cell membrane. During apoptosis, PtdSer is exposed to the outer leaflet of the cell membrane. The MerTK ligands ProS and Gas6 contain gamma-carboxylated glutamic acid residues near their N-terminal domains, and gamma-carboxylation of the glutamic acid domain enables binding to phosphatidylserine. Gas6 or ProS binds to PtdSer on apoptotic cells and simultaneously binds to MerTK on phagocytic cells. Binding of such ligands to MerTK activates efferocytosis.

As shown in the Examples below, anti-MerTK antibodies of the disclosure were effective in reducing or reducing efferocytosis in a variety of phagocytic cells. An anti-MerTK antibody that blocks only ProS from binding to MerTK showed potent inhibition of efferocytosis with a comparable IC50 to an anti-MerTK antibody that blocks both ProS and Gas6 from binding to MerTK. Given that genetic defects in both ProS and Gas6 are required for the development of blindness due to retinal degradation (single gene knockouts of ProS or Gas6 did not cause retinal lesions), ProS-specific blockers Anti-MerTK antibodies may improve the therapeutic index for use in anti-tumor responses without inducing ocular toxicity problems.

Accordingly, in some embodiments, anti-MerTK antibodies of the disclosure reduce or reduce efferocytosis by phagocytic cells. In some embodiments, an anti-MerTK antibody of the disclosure reduces or reduces efferocytosis by macrophages. In some embodiments, anti-MerTK antibodies of the present disclosure reduce or reduce efferocytosis by dendritic cells. In some embodiments, anti-MerTK antibodies of the present disclosure reduce or reduce efferocytosis by bone marrow-derived macrophages. In some embodiments, an anti-MerTK antibody of the present disclosure reduces efferocytosis by phagocytic cells by at least 10%, compared to the level of efferocytosis in phagocytic cells in the absence of the anti-MerTK antibody, by at least 20%, at least 25%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95% reduction or reduction. The percent reduction in efferocytosis can be determined using standard methods known to those skilled in the art, such as those described herein in Example 11.

In some embodiments, the anti-MerTK antibodies of the disclosure are evaluated by the methods described herein in the Examples below (e.g., Example 11) to promote efferocytosis by phagocytic cells (e.g., human macrophages). is reduced or lowered in the IC50 range of about 0.13 nM to about 30 nM. In some embodiments, an anti-MerTK antibody of the present disclosure inhibits phagocyte-mediated efferocytosis with an IC50 value in the range of 0.13 nM to 1.0 nM, in the range of 1 nM to 5 nM, in the range of 5 nM to 10 nM, or in the range of 10 nM to Decrease or decrease in the range of 30 nM.

Blocking efferocytosis promotes M1-like macrophage polarization and produces inflammatory cytokines (e.g., TNF, IFN, IL-12) and cytotoxic cells, such as CD8+ T cells, that mediate anti-tumor immunity. and increased recruitment of natural killer cells. By reducing efferocytosis by phagocytic cells, the anti-MerTK antibodies of the disclosure increase M1-like macrophage polarization as well as TNF, IFN, IL-6, IL-1, IL-12, chemokines (CX- C motif) ligand 1 (CXCL-1, KC), monocyte chemoattractant protein-1 (MCP1, CCL2), macrophage inflammatory protein-1-alpha (MIP-1α, CCL3), and/or macrophage inflammatory protein Effective in increasing the production, expression and/or secretion of inflammatory cytokines/chemokines including -1-beta (MIP-1β, CCL4). Accordingly, in some embodiments, anti-MerTK antibodies of the present disclosure increase M1-like macrophage polarization. In some embodiments, anti-MerTK antibodies of the disclosure increase macrophage production, expression, or secretion of one or more inflammatory cytokines. In some embodiments, the anti-MerTK antibodies of the present disclosure induce macrophage production of TNF, IFN, IL-6, IL-1, IL-12, CXCL-1, MCP1, MIP-1α, and/or MIP-1β , expression, or secretion.

Accordingly, in some embodiments, provided herein is a method of increasing the production, expression, and/or secretion of an inflammatory cytokine in a subject in need thereof, the method comprising: administering to said subject an anti-MerTK antibody of the present disclosure such that production, expression and/or secretion of one or more inflammatory cytokines in said subject is increased. In some embodiments, TNF production, expression and/or secretion is increased. In some embodiments, IFN production, expression, and/or secretion is increased. In some embodiments, IL-12 production, expression and/or secretion is increased. In some embodiments, CXCL-1 production, expression, and/or secretion is increased. In some embodiments, MCP1 production, expression and/or secretion is increased. In some embodiments, MIP-1α production, expression and/or secretion is increased. In some embodiments, MIP-1β production, expression and/or secretion is increased.

In some embodiments, provided herein is a method of increasing M1-like macrophage polarization in a subject in need thereof, the method comprising: increasing M1-like macrophage polarization in the subject; administering to said subject an anti-MerTK antibody of the present disclosure to increase. Increased M1-like macrophage polarization is associated with one or more of the various methods known to those skilled in the art, including TNF, IFN, IL-12, CXCL1, MCP1, MIP-1α, and/or MIP-1β. measured by increased production, expression, or secretion of sexual cytokines.

An association between efferocytosis and cancer progression has been described. For example, blockade of efferocytosis using annexin V, which blocks PtdSer from interacting with the phagocyte efferocytotic machinery, substantially reduces tumor progression and metastasis (Stach et al, 2000, Cell Death Diff, 7:911, Bondanza et al, 2004, J Exp Med, 200:1157, Werfel and Cook, 2018, Sem Immunopathology, 40:545-554). Moreover, MerTK, like its PtdSer bridging ligand Gas6, correlates with poor prognosis and poor survival in many human cancers (Graham et al, 2014, Nat Rev Cancer, 14:769, Linger et al. , 2010, Expert Opin The Targets, 14:1073-1090, Wang et al, 2013, Oncogene, 32:872, Jansen et al, 2011, J Proteome Res, 11:728-735, Tworkoski et al, 2011, Mol Can Res, p. molcanres-0512, Graham et al, 2006, Clin Cancer Res, 12:2662-2669, Keating et al, 2006, Oncogene, 25:6092). Accordingly, anti-MerTK antibodies of the disclosure that reduce efferocytosis by phagocytic cells are, in turn, effective in reducing tumor progression and metastasis.

In cynomolgus studies, in some cases, anti-MerTK antibodies that block binding to both Gas6 and ProS (e.g., the anti-MerTK antibody MTK-16) block binding of ProS to MerTK, but not Gas6 to MerTK. showed lower in vivo toxicity (e.g., weight loss) compared to that observed in cynomolgus monkeys administered anti-MerTK antibodies (e.g., anti-MerTK antibodies MTK-15 or MTK-29) that do not block the binding of rice field. Thus, in some embodiments, an anti-MerTK antibody of the disclosure that blocks binding of both Gas6 and ProS to MerTK blocks ProS binding to MerTK, but does not block Gas6 binding to MerTK May exhibit reduced systemic in vivo toxicity compared to anti-MerTK antibodies of the present disclosure. The anti-MerTK antibody MTK-16 (which blocks the binding of both Gas6 and ProS to MerTK) binds to the Ig1 domain of the MerTK protein, whereas the anti-MerTK antibodies MTK-15 and MTK-29 (which block ProS binding to MerTK) , but not Gas6 binding to MerTK) binds to both the Ig2 and FN1 domains of the MerTK protein. Thus, in some embodiments, an anti-MerTK antibody that binds the Ig1 domain of MerTK may exhibit lower systemic in vivo toxicity than an anti-MerTK antibody that binds both the Ig2 and FN1 domains of MerTK.

A. Exemplary Antibodies and Certain Other Antibody Embodiments In some embodiments, provided herein are: , 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, and 98, (b ) SEQ. , 123, and 124; , 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, and 157. HVR-H3, (d) SEQ ID NOs: 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177 , 178, 179, 180, 181, 182, 183, 184, 185, and 186, (e) SEQ ID NOs: 187, 188, 189, 190, 191, 192 , 193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203, 204, and 205, and (f) SEQ ID NO: 207, and An anti-MerTK antibody comprising at least 1, 2, 3, 4, 5, or 6 HVRs selected from HVR-L3 comprising an amino acid sequence selected from the group consisting of 233.

In some embodiments, provided herein are (a) SEQ ID NOs: 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, , 90, 91, 92, 93, 94, 95, 96, 97, and 98, (b) SEQ ID NOs: 99, 100, 101, 102, 103, 104 , 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, and 124. and (c) SEQ. at least one selected from HVR-H3 comprising an amino acid sequence selected from the group consisting of 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156 and 157 An anti-MerTK antibody comprising at least two or all three V _H HVR sequences.

In some embodiments, provided herein are: , 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, and 186; (b) SEQ ID NO: 187; , 188, 189, 190, 191, 192, 193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203, 204, and 205. L2 and (c) SEQ ID NOs: 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227, an anti-MerTK comprising at least one, at least two, or all three V _L HVR sequences selected from HVR-L3 comprising an amino acid sequence selected from the group consisting of 228, 229, 230, 231, 232 and 233 is an antibody.

In some embodiments, provided herein are (a)(i) SEQ ID NOS: 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, HVR-H1 comprising an amino acid sequence selected from the group consisting of 88, 89, 90, 91, 92, 93, 94, 95, 96, 97 and 98; (ii) SEQ ID NOs: 99, 100, 101, 102; 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, and 124 and (iii) SEQ. , 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, and 157. a _VH domain comprising one, at least two, or all three _VH HVR sequences and (b)(i) SEQ ID NOs: 158, 159, 160, 161, 162, 163, 164, 165, 166, 167 , 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, and 186. the group consisting of HVR-L1, (ii) SEQ ID NOs: 187, 188, 189, 190, 191, 192, 193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203, 204, and 205 and (iii) SEQ ID NOs: 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222, at least one, at least two, or three selected from HVR-L3 comprising an amino acid sequence selected from the group consisting of 223, 224, 225, 226, 227, 228, 229, 230, 231, 232 and 233 An anti-MerTK antibody containing a V _L domain containing all V _L HVR sequences.

In some embodiments, provided herein are (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:75, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:99, (c) sequence (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 158; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) the amino acid sequence of SEQ ID NO: 207. HVR-L3 comprising the sequence, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:76, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:100, (c) HVR- comprising the amino acid sequence of SEQ ID NO:126 H3, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 159, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 208, (a) ) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 77, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 101, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 127, (d) SEQ ID NO: 160 (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 188; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 209; (a) comprising the amino acid sequence of SEQ ID NO: 75. HVR-H1, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 99, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 128, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 158, ( e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 78, (b) SEQ ID NO: (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 129; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 161; (e) the amino acid sequence of SEQ ID NO: 189. and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:211, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:75, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:103 (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 130, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 158, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:212; (a) HVR-H1 containing the amino acid sequence of SEQ ID NO: 77, (b) HVR-H2 containing the amino acid sequence of SEQ ID NO: 101, (c) HVR-H3 containing the amino acid sequence of SEQ ID NO: 127, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 188; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 209; (a) the amino acid sequence of SEQ ID NO: 75. (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 99; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 131; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 163 (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 213; (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 79; HVR-H2 comprising the amino acid sequence of SEQ ID NO: 104, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 132, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 164, (e) the amino acid of SEQ ID NO: 190 HVR-L2 comprising the sequence, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:214, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:80, (b) HVR comprising the amino acid sequence of SEQ ID NO:105. -H2, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 133, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 165, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 191, and ( f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:215, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:81, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:106, (c) SEQ ID NO:134 (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 166; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 192; and (f) the amino acid sequence of SEQ ID NO: 216. (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:82; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:107; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:135; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 167, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 193, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 217, (a) sequence HVR-containing the amino acid sequence numbered 77 H1, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 108, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 136, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 167, (e) (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:209; (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:75; (b) HVR-H1 comprising the amino acid sequence of SEQ ID NO:109; HVR-H2 comprising the amino acid sequence, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 137, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 168, (e) HVR comprising the amino acid sequence of SEQ ID NO: 187 -L2, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 218, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 83, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 999, ( c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 138, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 158, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187, and (f) SEQ ID NO: (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:84; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:99; (c) the amino acid sequence of SEQ ID NO:139. (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 169; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 195; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 219. , (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:85, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:99, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:140, (d) sequence (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 196; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 222; (a) the amino acid sequence of SEQ ID NO: 86. (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 99; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 141; (d) HVR- comprising the amino acid sequence of SEQ ID NO: 171 L1, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 191, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 221, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 87, (b) ) HV comprising the amino acid sequence of SEQ ID NO: 110 (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 142; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 172; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 197; (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 222, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 88, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 99, (c) SEQ ID NO: (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 173; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 191; and (f) the amino acid sequence of SEQ ID NO: 223. (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:89; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:111; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:143 (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 173, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 198, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 221, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 112, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 144, (d) amino acid of SEQ ID NO: 174 (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 199; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 224; (a) HVR comprising the amino acid sequence of SEQ ID NO: 91. -H1, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 113, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 145, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 175, (e) ) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 200, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 225, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) SEQ ID NO: 114. (c) HVR-H3 containing the amino acid sequence of SEQ ID NO: 146; (d) HVR-L1 containing the amino acid sequence of SEQ ID NO: 176; (e) containing the amino acid sequence of SEQ ID NO: 201 HVR-L2, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:226, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:92, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:115, (c) the amino acid sequence of SEQ ID NO: 147 (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 177; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 195; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 227. , (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 93, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 116, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 148, (d) sequence (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 188; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 209; (a) the amino acid sequence of SEQ ID NO: 94. (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 117; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 149; (d) HVR- comprising the amino acid sequence of SEQ ID NO: 179 L1, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 195, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 228, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 95, (b) ) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 118, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 150, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 180, (e) SEQ ID NO: 187 HVR-L2 comprising the amino acid sequence, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:229, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:95, (b) comprising the amino acid sequence of SEQ ID NO:119 HVR-H2, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 151, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 181, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 208, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 120, (c) SEQ ID NO: (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 182; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 202; and (f) the amino acid sequence of SEQ ID NO: 230. (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:96; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:118; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:153 , (d) the amino acid of SEQ ID NO: 183 (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 202; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 230; (a) the amino acid sequence of SEQ ID NO: 96. HVR-H1 comprising, (b) HVR- comprising the amino acid sequence of SEQ ID NO: 121
H2, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 154, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 181, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187, and (f) ) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 122, (c) SEQ ID NO: 155 (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 184; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 203; and (f) the amino acid sequence of SEQ ID NO: 231. HVR-L3, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 97, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 123, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 156, ( d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 185, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 204, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 232, (a) SEQ ID NO: (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 124; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 157; (d) the amino acid sequence of SEQ ID NO: 186. (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:205; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:233.

In another aspect, the anti-MerTK antibody comprises at least 90%, 91 %, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100 _% sequence identity. In certain embodiments, SEQ ID NOs: 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 , 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, and 39, at least 90%, 91%, 92 _VH sequences having %, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity may be substituted (e.g. conservative substitutions), insertions, or deletions, but an anti-MerTK antibody containing that sequence retains the ability to bind to MerTK. In certain embodiments, SEQ ID NOs: 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 , 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, or 39 with a total of 1 to 10 amino acids substituted, inserted, and/or deleted there is In certain embodiments, SEQ ID NOs: 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 a total of 1 to 5 amino acids have been substituted, inserted and/or deleted in . In certain embodiments, substitutions, insertions, or deletions occur in regions outside the HVR (ie, in the FRs). Optionally, said anti-MerTK antibody is SEQ ID NO: 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 , 25, ₂₆ , 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, or 39, including post-translational modifications of the sequence. In certain embodiments, the _VH is (a) an HVR-H1 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs:75-98, (b) an amino acid selected from the group consisting of SEQ ID NOs:99-124 (c) HVR-H3 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 125-157;

In another aspect, , 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, and 74, at least 90%, 91%, 92%, An anti-MerTK antibody is provided comprising a light chain variable domain (V _L ) having 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity. In certain embodiments, SEQ ID NOs: 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60 , 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, and 74, at least 90%, 91%, 92 V _L sequences having %, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity are substituted (e.g., conservative substitutions), insertions, or deletion, but an anti-MerTK antibody containing that sequence retains the ability to bind to MerTK. In some embodiments, SEQ. a total of 1-10 amino acids substituted, inserted and/or deleted in . In certain embodiments, SEQ ID NOs: 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60 , 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, or 74 with a total of 1-5 amino acids substituted, inserted, and/or deleted there is In certain embodiments, the substitution, insertion, or deletion occurs in regions outside the HVR (ie, in the FRs). Optionally, said anti-MerTK antibody is SEQ ID NO: 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59 , 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73 _, or 74, including post-translational modifications of the sequence. In certain embodiments, said V _L is (a) an HVR-L1 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 158-186, (b) an amino acid selected from the group consisting of SEQ ID NOs: 187-205 (c) HVR-L3 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 207-233.

In some embodiments, an anti-MerTK antibody is provided comprising a V _H of any of the above embodiments and a V _L of any of the above embodiments. In some embodiments, provided herein is an anti-MerTK antibody comprising the V _H of any of the above embodiments and the V _L of any of the above embodiments. In one embodiment, the antibody comprises the V _H and V _L sequences of SEQ ID NOs: 5-39 and SEQ ID NOs: 40-74, respectively, including post-translational modifications of those sequences.

In some embodiments, provided herein is an anti-MerTK antibody comprising a heavy chain variable domain (V _H ) and a light chain variable domain (V _L ), wherein the V _H and V _L are defined as follows: is selected from the group consisting of: _VH comprising the amino acid sequence of SEQ ID NO:5 and VL comprising the amino acid sequence of SEQ ID NO:40, _VH comprising the amino acid sequence of SEQ ID NO:6 and _V comprising the amino acid sequence of SEQ ID NO:41 _L , VH containing the amino acid sequence of SEQ ID NO:7 and _VL containing the amino acid sequence of SEQ ID NO:42, _VH containing the amino acid sequence of SEQ ID NO:8 and _VL containing the amino acid sequence of SEQ ID NO:43, _SEQ ID NO:9 V _H containing the amino acid sequence and V L containing the amino acid sequence of SEQ ID _NO : 44, V _H containing the amino acid sequence of SEQ ID NO: 10 and V _L containing the amino acid sequence of SEQ ID NO: 45, V _H containing the amino acid sequence of SEQ ID NO: 11 and V _L containing the amino acid sequence of SEQ ID NO: 46, V _H containing the amino acid sequence of SEQ ID NO: 12 and V _L containing the amino acid sequence of SEQ ID NO: 47, V _H containing the amino acid sequence of SEQ ID NO: 13 and the amino acids of SEQ ID NO: 48 V _L containing the sequence, V _H containing the amino acid sequence of SEQ ID NO: 14 and V L containing the amino acid sequence of SEQ ID NO: 49 _{, V H containing the amino acid sequence of SEQ ID NO: 15 and V L containing the} amino acid sequence of SEQ ID NO: 50, V H containing the amino acid sequence of SEQ ID NO: 16 and V _L containing the amino acid sequence of SEQ ID NO: 51 _{, V H containing the amino acid sequence of SEQ ID NO: 17 and V L containing the} amino acid sequence of SEQ ID NO: 52, and the amino acid sequence of SEQ ID NO: 18 and a V _L comprising the amino acid sequence of SEQ ID NO: 53, a V _H comprising the amino acid sequence of SEQ ID NO: 19 and a V _L comprising the amino acid sequence of SEQ _ID NO: 54, a V _H comprising the amino acid sequence of SEQ ID NO: 20 and the sequence V _L containing the amino acid sequence of SEQ ID NO: 55, V H containing the amino acid sequence of SEQ ID NO: 21 and _VL containing the amino acid sequence _{of SEQ ID NO: 56, V H containing} the amino acid sequence of SEQ ID NO: 22 and the amino acid sequence of SEQ ID NO: 57 V _L containing the amino acid sequence of SEQ ID NO: 23, V _L containing the amino acid sequence of SEQ ID NO: 58 _, V _H containing the amino acid sequence of SEQ ID NO: 24 and V _L containing the amino acid sequence of SEQ ID NO: 59, SEQ ID NO: V _H comprising the amino acid sequence of SEQ ID NO: 25 and V _L comprising the amino acid sequence of SEQ ID NO: 60, V _H comprising the amino acid sequence of SEQ ID NO: 26 and SEQ ID NO: 61 V _L containing the amino acid sequence, V _H containing the amino acid sequence of SEQ ID NO: 27 and V _{L containing the amino acid sequence of SEQ ID NO: 62, V H containing} the amino acid sequence of SEQ ID NO: 28 and V _L containing the amino acid sequence of SEQ ID NO: 63 , V _H containing the amino acid sequence of SEQ ID NO: 29 and V _{L containing the amino acid sequence of SEQ ID NO: 64, V H containing} the amino acid sequence of SEQ ID NO: 30 and V _L containing the amino acid sequence of SEQ ID NO: 65, the amino acid of SEQ ID NO: 31 V _H containing the sequence and V _L containing the amino acid sequence of SEQ ID NO: 66, V _H containing the amino acid sequence of SEQ ID NO: 32 and V _L containing the amino acid sequence of SEQ ID NO: 67, V _H containing the amino acid sequence of SEQ ID NO: 33 and V _{L containing the amino acid sequence of SEQ ID NO: 68, V H} containing the amino acid sequence of SEQ ID NO: 34 and V _L containing the amino acid sequence _{of SEQ ID NO: 69, V H containing} the amino acid sequence of SEQ ID NO: 35 and the amino acid sequence of SEQ ID NO: 70 V _L comprising the amino acid sequence of SEQ ID NO: 36 and V _L comprising the amino acid sequence of SEQ ID NO: 71 _{, V H comprising the amino acid sequence of SEQ ID NO: 37 and V L comprising the} amino acid sequence of SEQ ID NO: 72, the sequence A VH comprising the amino acid sequence of SEQ ID NO:38 and a _VL comprising the amino acid sequence of SEQ ID NO:73, and a _VH comprising the amino acid sequence of SEQ ID NO:39 and a _VL comprising the amino acid sequence of SEQ ID NO _: 74.

In some embodiments, provided herein consists of (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:83, (b) SEQ ID NOs:99, 329, 330, 331, 332, and 333 (c) HVR-H3 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 138, 334, 335, 336, 337, 338, and 339; (d) (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) SEQ ID NO: An anti-MerTK antibody comprising at least 1, 2, 3, 4, 5, or 6 HVRs selected from HVR-L3 comprising a 210 amino acid sequence.

In some embodiments, provided herein consists of (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:83, (b) SEQ ID NOs:99, 329, 330, 331, 332, and 333 and (c) HVR-H3 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 138, 334, 335, 336, 337, 338, and 339. is an anti-MerTK antibody comprising at least one, at least two, or all three _VH HVR sequences.

In some embodiments, provided herein are (a) HVR-L1 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 158, 340, 341, 342, 343, and 344; a) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (c) HVR-L3 comprising the amino acid sequence of _SEQ ID NO: 210. An anti-MerTK antibody comprising:

In some embodiments, provided herein are (a) (i) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 83, (ii) SEQ ID NOs: 99, 329, 330, 331, 332, and HVR-H2 comprising an amino acid sequence selected from the group consisting of 333 and (iii) HVR-H3 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 138, 334, 335, 336, 337, 338, and 339 and ₍ b) (i) SEQ _ID NOs: 158, 340, 341, 342, 343, and 344. at least one selected from HVR-L1 comprising an amino acid sequence selected from the group, (ii) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187, and (iii) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210 , an anti-MerTK antibody comprising a V _L domain comprising at least two, or all three V _L HVR sequences.

In some embodiments, provided herein are (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:83, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:99, (c) sequence (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 158; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) the amino acid sequence of SEQ ID NO: 210. HVR-L3 comprising the sequence, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:83, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:329, (c) HVR- comprising the amino acid sequence of SEQ ID NO:334 H3, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 158, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210, (a) ) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 83, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 330, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 138, (d) SEQ ID NO: 158 (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210; (a) comprising the amino acid sequence of SEQ ID NO: 83. HVR-H1, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 329, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 138, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 340, ( e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 83, (b) SEQ ID NO: (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 138; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 341; (e) the amino acid sequence of SEQ ID NO: 187. and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:210, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:83, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:329 (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:335, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:341, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:187, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:210 , (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 83, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 331, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 138, (d) sequence (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210; (a) the amino acid sequence of SEQ ID NO: 83. (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 329; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 138; (d) HVR- comprising the amino acid sequence of SEQ ID NO: 342 L1, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 83, (b) ) HVR-H2 comprising the amino acid sequence of SEQ ID NO:329, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:336, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:341, (e) SEQ ID NO:187 HVR-L2 comprising the amino acid sequence, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:210, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:83, (b) comprising the amino acid sequence of SEQ ID NO:329 HVR-H2, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:337, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:343, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:187, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 83, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 332, (c) SEQ ID NO: (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:341; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:187; and (f) the amino acid sequence of SEQ ID NO:210. (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:83; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:333; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:334 (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 158, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210, (a) HV comprising the amino acid sequence of SEQ ID NO:83 R-H1, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 332, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 336, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 341, ( e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 83, (b) SEQ ID NO: (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 339; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 344; (e) the amino acid sequence of SEQ ID NO: 187. and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:210, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:83, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:329 (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 138, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 158, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187, and (f) An anti-MerTK antibody comprising HVR-L3 comprising the amino acid sequence of SEQ ID NO:210.

In another aspect, the anti-MerTK antibody has an amino acid sequence selected from the group consisting of Heavy chain variable domains (V _H ) containing arrays. In certain embodiments, for an amino acid sequence selected from the group consisting of SEQ ID NOS: 19, 234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, and 246, _VH sequences having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity are substituted (e.g. , conservative substitutions), insertions, or deletions, but an anti-MerTK antibody containing that sequence retains the ability to bind to MerTK. In certain embodiments, a total of 1-10 amino acids are substituted in SEQ ID NO: 19, 234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, or 246; inserted and/or deleted. In certain embodiments, a total of 1-5 amino acids are substituted in SEQ ID NO: 19, 234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, or 246; inserted and/or deleted. In certain embodiments, substitutions, insertions, or deletions occur in regions outside the HVR (ie, in the FRs). Optionally, the anti-MerTK antibody comprises the _VH sequence of SEQ ID NOs: 19, 234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, or 246 after translation of that sequence. Including modifications. In certain embodiments, said _VH is selected from the group consisting of (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:83, (b) SEQ ID NOS:99, 329, 330, 331, 332, and 333 one selected from HVR-H2 comprising an amino acid sequence, and (c) HVR-H3 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 138, 334, 335, 336, 337, 338, and 339. Contains one or three HVRs.

In another aspect, at least 90%, 91%, 92%, 93% for an amino acid sequence selected from the group consisting of , 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to a light chain variable domain (V _L ). In certain embodiments, at least 90%, 91%, 92%, V _L sequences having 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity are substituted (e.g., conservative substitutions), inserted, or deleted relative to the reference sequence. but an anti-MerTK antibody containing that sequence retains the ability to bind to MerTK. In some embodiments, a total of 1-10 amino acids have been substituted, inserted and/or deleted in SEQ ID NOs:54, 247, 248, 249, 250, 251, 252, 253, or 254. In certain embodiments, a total of 1-5 amino acids have been substituted, inserted and/or deleted in SEQ ID NOs:54, 247, 248, 249, 250, 251, 252, 253, or 254. In certain embodiments, the substitution, insertion, or deletion occurs in regions outside the HVR (ie, in the FRs). Optionally, said anti-MerTK antibody comprises the _VL sequence of SEQ ID NOs: 54, 247, 248, 249, 250, 251, 252, 253, or 254, including post-translational modifications of that sequence. In certain embodiments, the V _L is (a) HVR-L1 comprising an amino acid sequence selected from the group consisting of SEQ ID NOS: 158, 340, 341, 342, 343, and 344; HVR-L2 comprising the amino acid sequence, and (c) HVR-L3 comprising the amino acid sequence of SEQ ID NO:210.

In some embodiments, an anti-MerTK antibody is provided comprising a V _H of any of the above embodiments and a V _L of any of the above embodiments. In some embodiments, provided herein is an anti-MerTK antibody comprising the V _H of any of the above embodiments and the V _L of any of the above embodiments. In one embodiment, the antibody has SEQ ID NOs: 19, 234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, and 246 and SEQ ID NOs: 54, 247, 248, respectively , 249, 250, 251, ₂₅₂ , 253, and ₂₅₈ , including post-translational modifications of those sequences.

In some embodiments, provided herein is an anti-MerTK antibody comprising a heavy chain variable domain (V _H ) and a light chain variable domain (V _L ), wherein the V _H and V _L are defined as follows: is selected from the group consisting of: VH comprising the amino acid sequence of SEQ ID NO:19 and _VL comprising the amino acid sequence of SEQ ID NO:54, _VH comprising the amino acid sequence of SEQ ID NO:234 and _V comprising the amino acid sequence of SEQ ID NO:247 _L , VH comprising the amino acid sequence of SEQ ID _NO :235 and VL comprising the amino acid sequence of SEQ ID NO _: 247, _VH comprising the amino acid sequence of SEQ ID NO:236 and _VL comprising the amino acid sequence of SEQ ID NO:248, SEQ ID NO:236 V _H containing the amino acid sequence and V _L containing the amino acid sequence of SEQ ID NO: 249, V _H containing the amino acid sequence of SEQ ID NO: 237 and V _L containing the amino acid sequence of SEQ ID NO: 249, V _H containing the amino acid sequence of SEQ ID NO: 238 and V _L comprising the amino acid sequence of SEQ ID NO: 249, V _H comprising the amino acid sequence of SEQ ID NO: 239 and V _L comprising the amino acid sequence of SEQ ID NO: 250, V _H comprising the amino acid sequence of SEQ ID NO: 240 and the amino acids of SEQ ID NO: 251 V _L comprising the sequence, V _H comprising the amino acid sequence of SEQ ID NO: 241 and V _L comprising the amino acid sequence of SEQ ID NO: 252, V _H comprising the amino acid sequence of SEQ ID NO: 242 and V _L comprising the amino acid sequence of SEQ ID NO: 249, V _H comprising the amino acid sequence of SEQ ID NO: 243 and V _L comprising the amino acid sequence of SEQ ID NO: 247, V _H comprising the amino acid sequence of SEQ ID NO: 244 and V _L comprising the amino acid sequence of SEQ ID NO: 251, the amino acid sequence of SEQ ID NO: 245 and a V _L comprising the amino acid sequence of SEQ ID NO: 253, a V _H comprising the amino acid sequence of SEQ ID NO: 246 and a V _L comprising the amino _{acid sequence of SEQ ID NO: 247, and a V H comprising} the amino acid sequence of SEQ ID NO: 246 and A V _L comprising the amino acid sequence of SEQ ID NO:254.

In some embodiments, provided herein comprises an amino acid sequence selected from the group consisting of (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:84, (b) SEQ ID NO:99 and 329 (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 139; (d) HVR-L1 comprising an amino acid sequence selected from the group consisting of SEQ ID NO: 169 and 345; (e) the amino acid sequence of SEQ ID NO: 195 an anti-MerTK comprising at least 1, 2, 3, 4, 5, or 6 HVRs selected from HVR-L2 comprising the sequence, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:219 is an antibody.

In some embodiments, provided herein comprises an amino acid sequence selected from the group consisting of (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:84, (b) SEQ ID NO:99 and 329 An anti-MerTK antibody comprising at least one, at least two, or all three V _H HVR sequences selected from HVR-H2, and (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:139.

In some embodiments, provided herein is (a) an HVR-L1 comprising an amino acid sequence selected from the group consisting of SEQ ID NO: 169 and 345, (b) an amino acid sequence of SEQ ID NO: 195 An anti-MerTK antibody comprising at least one, at least two, or all three V _L HVR sequences selected from HVR-L2, and (c) HVR-L3 comprising the amino acid sequence of SEQ ID NO:219.

In some embodiments, provided herein are amino acids selected from the group consisting of: (a) (i) HVR-H1 comprising the amino acid sequence of SEQ ID NO:84, (ii) SEQ ID NO:99, 329 a VH domain comprising at least one, at least two, or all three _VH HVR sequences selected from HVR-H2 comprising the sequence, and (iii) HVR-H3 comprising the amino acid sequence of _SEQ ID NO: 139, and (b) (i) HVR-L1 comprising an amino acid sequence selected from the group consisting of SEQ ID NO: 169 and 345, (ii) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 195, and (iii) the amino acid of SEQ ID NO: 219 An anti-MerTK antibody comprising a V _L domain comprising at least one, at least two, or all three V _L HVR sequences selected from HVR-L3 comprising sequences. In some embodiments, provided herein are (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:84, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:99, (c) sequence (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 169; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 195; and (f) the amino acid sequence of SEQ ID NO: 219. (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:84; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:329; (c) HVR- comprising the amino acid sequence of SEQ ID NO:139 H3, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 169, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 195, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 219, and ( a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:84, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:99, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:139, (d) SEQ ID NO:345 (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:195; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:219.

In another aspect, the anti-MerTK antibody is at least 90%, 91%, 92%, 93%, 94%, 95%, Includes heavy chain variable domain (V _H ) sequences having 96%, 97%, 98%, 99% or 100% sequence identity. In certain embodiments, at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, A _VH sequence with 97%, 98%, or 99% identity contains substitutions (e.g., conservative substitutions), insertions, or deletions relative to the reference sequence, whereas anti-MerTK antibodies containing the sequences , retains the ability to bind to MerTK. In certain embodiments, a total of 1-10 amino acids have been substituted, inserted, and/or deleted in SEQ ID NOs:20, 255, or 256. In certain embodiments, a total of 1-5 amino acids have been substituted, inserted, and/or deleted in SEQ ID NOs:20, 255, or 256. In certain embodiments, substitutions, insertions, or deletions occur in regions outside the HVR (ie, in the FRs). Optionally, the anti-MerTK antibody comprises the _VH sequence of SEQ ID NO: 20, 255, or 256, including post-translational modifications of that sequence. In certain embodiments, the V _H is (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:84, (b) HVR-H2 comprising an amino acid sequence selected from the group consisting of SEQ ID NO:99 and 329, and (c) one, two, or three HVRs selected from HVR-H3 comprising the amino acid sequence of SEQ ID NO:139;

In another aspect, at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97% for an amino acid sequence selected from the group consisting of SEQ ID NOS:55, 257 and 258 , an anti-MerTK antibody comprising a light chain variable domain (V _L ) having 98%, 99%, or 100% sequence identity. In certain embodiments, at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, A V _L sequence having 97%, 98%, or 99% identity contains substitutions (e.g., conservative substitutions), insertions, or deletions relative to the reference sequence, whereas anti-MerTK antibodies containing the sequences , retains the ability to bind to MerTK. In some embodiments, a total of 1-10 amino acids have been substituted, inserted and/or deleted in SEQ ID NO:55, 257, or 258. In certain embodiments, a total of 1-5 amino acids have been substituted, inserted and/or deleted in SEQ ID NO:55, 257, or 258. In certain embodiments, the substitution, insertion, or deletion occurs in regions outside the HVR (ie, in the FRs). Optionally, the anti-MerTK antibody comprises the VL sequence of _SEQ ID NO:55, 257, or 258, including post-translational modifications of that sequence. In certain embodiments, said V _L is (a) HVR-L1 comprising an amino acid sequence selected from the group consisting of SEQ ID NO: 169 and 345, (b) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 195, and (c) one, two, or three HVRs selected from HVR-L3 comprising the amino acid sequence of SEQ ID NO:219;

In some embodiments, an anti-MerTK antibody is provided comprising a V _H of any of the above embodiments and a V _L of any of the above embodiments. In some embodiments, provided herein is an anti-MerTK antibody comprising the V _H of any of the above embodiments and the V _L of any of the above embodiments. In one embodiment, the antibody comprises the _VH and _VL sequences of SEQ ID NOs:20, 255, and 256 and SEQ ID NOs:55, 257, and 258, respectively, including post-translational modifications of those sequences.

In some embodiments, provided herein is an anti-MerTK antibody comprising a heavy chain variable domain (V _H ) and a light chain variable domain (V _L ), wherein the V _H and V _L are defined as follows: is selected from the group consisting of: VH comprising the amino acid sequence of SEQ ID NO:20 and _VL comprising the amino acid sequence of SEQ ID NO:55, _VH comprising the amino acid sequence of SEQ ID NO:255 and _V comprising the amino acid sequence of SEQ ID NO:257 _L and _VH comprising the amino acid sequence of SEQ ID NO:256 and _VL comprising the amino acid sequence of SEQ ID NO:258.

In some embodiments, provided herein are (a) HVR-H1 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 95, 346, and 347, (b) SEQ ID NOs: 119, 348 , 349, 350, 351, 352, 353 and 354, (c) an amino acid sequence selected from the group consisting of SEQ ID NOS: 151, 355 and 356; HVR-H3, (d) HVR-L1 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 181, 341, 357 and 358, (e) an amino acid sequence selected from the group consisting of SEQ ID NOs: 187 and 359 and (f) at least 1, 2, 3, 4 selected from HVR-L3 comprising an amino acid sequence selected from the group consisting of SEQ ID NOS: 208, 360, 361, and 362; Anti-MerTK antibodies containing 5 or 6 HVRs.

In some embodiments, provided herein are (a) HVR-H1 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 95, 346, and 347, (b) SEQ ID NOs: 119, 348 , 349, 350, 351, 352, 353, and 354; and (c) an amino acid sequence selected from the group consisting of SEQ ID NOs: 151, 355, and 356. An anti-MerTK antibody comprising at least one, at least two, or all three V _H HVR sequences selected from HVR-H3, including HVR-H3.

In some embodiments, provided herein is (a) an HVR-L1 comprising an amino acid sequence selected from the group consisting of SEQ ID NOS: 181, 341, 357, and 358, (b) SEQ ID NO: 187 and 359, and (c) HVR-L3 comprising an amino acid sequence selected from the group consisting of SEQ ID NOS: 208, 360, 361, and 362. An anti-MerTK antibody comprising one, at least two, or all three V _L HVR sequences.

In some embodiments, provided herein is a HVR-H1 comprising an amino acid sequence selected from the group consisting of: (a) (i) SEQ ID NOs: 95, 346, and 347; HVR-H2 comprising an amino acid sequence selected from the group consisting of 119, 348, 349, 350, 351, 352, 353, and 354; and (iii) SEQ ID NOs: 151, 355, and 356 a VH domain comprising at least one, at least two, or all three _VH HVR sequences selected from HVR-H3 comprising amino _acid sequences and (b)(i) SEQ ID NOs: 181, 341, 357, and 358 (ii) HVR-L2 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 187 and 359; and (iii) SEQ ID NOs: 208, 360, 361, and 362 amino _acid sequences selected from HVR- _L3 .

In some embodiments, provided herein are (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:95, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:119, (c) sequence (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 181; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) the amino acid sequence of SEQ ID NO: 208. (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:346; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:348; (c) HVR- comprising the amino acid sequence of SEQ ID NO:355 H3, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:341, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:187, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:360, (a) ) HVR-H1 comprising the amino acid sequence of SEQ ID NO:95, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:119, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:355, (d) SEQ ID NO:341 (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 361; (a) comprising the amino acid sequence of SEQ ID NO: 95. HVR-H1, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 349, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 356, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 341, ( e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 362, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 95, (b) SEQ ID NO: (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 356; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 341; (e) the amino acid sequence of SEQ ID NO: 359. and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:362, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:346, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:119 (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:356, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:341, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:359, and (f) HVR comprising the amino acid sequence of SEQ ID NO:362 -L3, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:95, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:350, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:356, (d) (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:359; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:362; (a) SEQ ID NO:347. (b) HVR-H2 containing the amino acid sequence of SEQ ID NO: 119; (c) HVR-H3 containing the amino acid sequence of SEQ ID NO: 356; (d) containing the amino acid sequence of SEQ ID NO: 341 (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:359; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:362; (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:95; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 119, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 356, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 341, (e) SEQ ID NO: HVR-L2 comprising the amino acid sequence of 187, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:362, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:95, (b) the amino acid sequence of SEQ ID NO:352. (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 356; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 341; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187 and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:362, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:95, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:353, (c) (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:341; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:359; and (f) HVR-L2 comprising the amino acid sequence of SEQ ID NO:362. HVR-L3 comprising the amino acid sequence, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:346, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:354, (c) HVR comprising the amino acid sequence of SEQ ID NO:356 -H3, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 341, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 359, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 363, ( a) the amino acid sequence of SEQ ID NO:346 (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:348; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:356; (d) HVR- comprising the amino acid sequence of SEQ ID NO:357 L1, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:359, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:362, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:346, (b) ) HVR-H2 comprising the amino acid sequence of SEQ ID NO:354, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:356, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:358, (e) SEQ ID NO:187 HVR-L2 comprising the amino acid sequence, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:362, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:95, (b) comprising the amino acid sequence of SEQ ID NO:348. HVR-H2, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 151, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 181, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187, and (f) an anti-MerTK antibody comprising HVR-L3 comprising the amino acid sequence of SEQ ID NO:208;

In another aspect, the anti-MerTK antibody is selected from the group consisting of: a heavy chain variable having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to the amino acid sequence of Includes domain (V _H ) sequences. In certain embodiments, an amino acid sequence selected from the group consisting of SEQ ID NOS: 33, 259, 260, 261, 262, 263, 264, 265, 266, 267, 268, 269, 270, 271, 272, and 273 A _VH sequence having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to a reference sequence , substitutions (eg, conservative substitutions), insertions, or deletions, but an anti-MerTK antibody containing that sequence retains the ability to bind MerTK. In certain embodiments, a total of 1-10 Amino acids have been substituted, inserted and/or deleted. In certain embodiments, a total of 1-5 Amino acids have been substituted, inserted and/or deleted. In certain embodiments, substitutions, insertions, or deletions occur in regions outside the HVR (ie, in the FRs). Optionally, said anti-MerTK antibody comprises the _VH sequence of Including post-translational modifications of sequences. In certain embodiments, the V _H is (a) HVR-H1 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 95, 346, and 347, (b) SEQ ID NOs: 119, 348, 349, 350, from HVR-H2 comprising an amino acid sequence selected from the group consisting of 351, 352, 353 and 354, and (c) HVR-H3 comprising an amino acid sequence selected from the group consisting of SEQ ID NOS: 151, 355 and 356 Includes 1, 2 or 3 HVRs to choose from.

In another aspect, an amino acid sequence selected from the group consisting of: a light chain variable domain (V _L ) provides anti-MerTK antibodies. In certain embodiments, a A V _L sequence having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to the amino acid sequence to the reference sequence In contrast, anti-MerTK antibodies containing substitutions (eg, conservative substitutions), insertions, or deletions, but containing that sequence retain the ability to bind MerTK. In some embodiments, 1-10 total amino acids have been substituted, inserted and/or deleted. In certain embodiments, 1-5 total amino acids have been substituted, inserted and/or deleted. In certain embodiments, the substitution, insertion, or deletion occurs in regions outside the HVR (ie, in the FRs). Optionally, the anti-MerTK antibody has the _VL sequence of SEQ ID NOs: 68, 274, 275, 276, 277, 278, 279, 280, 281, 282, 283, 284, 285, 286, 287, 288, or 289 , including post-translational modifications of the sequence. In certain embodiments, the V _L is (a) an HVR-L1 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 181, 341, 357, and 358, (b) the group consisting of SEQ ID NOs: 187 and 359 and (c) HVR-L3 comprising an amino acid sequence selected from the group consisting of SEQ ID NOS: 208, 360, 361, and 362. Contains 3 HVRs.

In some embodiments, an anti-MerTK antibody is provided comprising a V _H of any of the above embodiments and a V _L of any of the above embodiments. In some embodiments, provided herein is an anti-MerTK antibody comprising the V _H of any of the above embodiments and the V _L of any of the above embodiments. In one embodiment, the antibody has SEQ ID NOs: 33, 259, 260, 261, 262, 263, 264, 265, 266, 267, 268, 269, 270, 271, 272, and 273 and SEQ ID NO: 68, respectively , 274, 275, 276, 277, 278, 279, 280, 281, 282, ₂₈₃ , 284, 285, 286, 287 _{, 288} , and 289 by post-translational modification of those sequences. include include.

In some embodiments, provided herein is an anti-MerTK antibody comprising a heavy chain variable domain (V _H ) and a light chain variable domain (V _L ), wherein the V _H and V _L are defined as follows: is selected from the group consisting of: VH comprising the amino acid sequence of SEQ ID NO:33 and _VL comprising the amino acid sequence of SEQ ID NO:68, _VH comprising the amino acid sequence of SEQ ID NO:259 and _V comprising the amino acid sequence of SEQ ID NO:274 _L , VH comprising the amino acid sequence of SEQ ID NO:260 and _VL comprising the amino acid sequence of SEQ ID NO:275, _VH comprising the amino acid sequence of SEQ ID NO:261 and _VL comprising the amino acid sequence of SEQ ID NO:276, _SEQ ID NO:262 VH comprising the amino acid sequence and _VL comprising the amino acid sequence of SEQ ID NO:277, _VH comprising the amino acid sequence of SEQ ID NO:263 and _VL comprising the amino acid sequence of SEQ ID NO _: 277, VH comprising _the amino acid sequence of SEQ ID NO:264 and V _L comprising the amino acid sequence of SEQ ID NO: 277, V _H comprising the amino acid sequence of SEQ ID NO: 265 and V _L comprising the amino acid sequence of SEQ ID NO: 277, V _H comprising the amino acid sequence of SEQ ID NO: 266 and the amino acids of SEQ ID NO: 277 V _L comprising the sequence, V _H comprising the amino acid sequence of SEQ ID NO: 267 and V _L comprising the amino acid sequence of SEQ ID NO: 278, V _H comprising the amino acid sequence of SEQ ID NO: 268 and V _L comprising the amino acid sequence of SEQ ID NO: 279, V _H comprising the amino acid sequence of SEQ ID NO: 269 and V _L comprising the amino acid sequence of SEQ ID NO: 279, V _H comprising the amino acid sequence of SEQ ID NO: 264 and V _L comprising the amino acid sequence of SEQ ID NO: 280, the amino acid sequence of SEQ ID NO: 270 and a V _L comprising the amino acid sequence of SEQ ID NO: 281, a V _H comprising the amino acid sequence of SEQ ID NO: 265 and a V _L comprising the amino acid sequence of SEQ ID NO: 282, a V _H comprising the amino acid sequence of SEQ ID NO: 264 _and the sequence V _{L containing the amino acid sequence of SEQ ID NO: 283, V H} containing the amino acid sequence of SEQ ID NO: 271 and V _L containing the amino acid sequence _{of SEQ ID NO: 284, V H containing} the amino acid sequence of SEQ ID NO: 272 and the amino acid sequence of SEQ ID NO: 285 V _L containing the amino acid sequence of SEQ ID NO: 271, V _L containing the amino acid sequence of SEQ ID NO: 286, V _H containing the amino _{acid sequence of SEQ ID NO: 273 and V L containing} the amino acid sequence of SEQ ID NO: 287, SEQ ID NO: _VH and SEQ ID NO: 2 comprising a sequence of 273 amino acids A V _L comprising the amino acid sequence of 88, and a V H comprising the amino acid sequence of SEQ ID _NO :273 and a V _L comprising the amino acid sequence of SEQ ID NO:289.

In some embodiments, provided herein consists of (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) SEQ ID NOs: 122, 364, 365, 366, 367, and 368 (c) HVR-H3 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 155, 373, 374, and 375; (d) SEQ ID NOs: 184, 376; HVR-L1 comprising an amino acid sequence selected from the group consisting of 377, 378, 379, 380, 381, 382, 383, 384, 385, 386, and 387; (e) SEQ ID NOs: 203, 388, 389, 390; and 391, and (f) HVR-L3 comprising an amino acid sequence selected from the group consisting of SEQ ID NOS: 231, 392, 393, and 394. An anti-MerTK antibody comprising 1, 2, 3, 4, 5, or 6 HVRs.

In some embodiments, provided herein consists of (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) SEQ ID NOS: 122, 364, 365, 366, 367, and 368 (c) at least one HVR-H3 comprising an amino acid sequence selected from the group consisting of SEQ ID NOS: 155, 373, 374, and 375; An anti-MerTK antibody containing two or all three V _H HVR sequences.

In some embodiments, provided herein are: (a) the group consisting of (b) HVR-L2 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 203, 388, 389, 390, and 391; and (c) SEQ ID NO: 203, an anti-MerTK antibody comprising at least one, at least two, or all three V _L HVR sequences selected from HVR-L3 comprising an amino acid sequence selected from the group consisting of 388, 389, 390, and 391 .

In some embodiments, provided herein are (a) (i) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (ii) SEQ ID NOs: 122, 364, 365, 366, 367, and HVR-H2 comprising an amino acid sequence selected from the group consisting of 368; and (iii) at least one HVR-H3 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 155, 373, 374, and 375 a _VH domain comprising one, at least two, or all three _VH HVR sequences and (b)(i) SEQ ID NOs: 184, 376, 377, 378, 379, 380, 381, 382, 383, 384, 385 , 386 and 387, (ii) HVR-L2 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 203, 388, 389, 390 and 391; and (iii) at least one, at least two, or all three V _L HVR sequences selected from HVR-L3 comprising an amino acid sequence selected from the group consisting of SEQ ID NOS: 231, 392, 393, and 394 is an anti-MerTK antibody comprising a _VL domain containing

In some embodiments, provided herein are (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:122, (c) sequence (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 184; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 203; and (f) the amino acid sequence of SEQ ID NO: 231. (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:90; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:364; (c) HVR- comprising the amino acid sequence of SEQ ID NO:373 H3, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:376, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:388, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:231, (a) (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 364; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155; (d) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 377 (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 203; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 231; (a) comprising the amino acid sequence of SEQ ID NO: 90. HVR-H1, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 364, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 374, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 378, ( e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:231, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:95, (b) SEQ ID NO: (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 356; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 341; (e) the amino acid sequence of SEQ ID NO: 359. and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:362, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:365 (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 276, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 203, and (f) HVR-L comprising the amino acid sequence of SEQ ID NO:392 3, (a) HVR-H1 containing the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 containing the amino acid sequence of SEQ ID NO: 364, (c) HVR-H3 containing the amino acid sequence of SEQ ID NO: 155, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:376, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:389, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:231 (a) SEQ ID NO:90 HVR-H1 comprising the amino acid sequence, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:364, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:155, (d) HVR comprising the amino acid sequence of SEQ ID NO:379 -L1, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 203, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 231, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, ( b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:366, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:155, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:380, (e) SEQ ID NO:203 and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 231, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) the amino acid sequence of SEQ ID NO: 364. (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:373; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:381; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:231, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:367, (c) sequence (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:382; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203; and (f) the amino acid sequence of SEQ ID NO:231. HVR-L3 comprising the sequence, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:368, (c) HVR- comprising the amino acid sequence of SEQ ID NO:155 H3, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:383, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:231, (a) ) H comprising the amino acid sequence of SEQ ID NO:90 VR-H1, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 364, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 374, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 384, ( e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 203, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 231, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) SEQ ID NO: (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 376; (e) the amino acid sequence of SEQ ID NO: 203. and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:393, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:364. (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 378, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 203, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:231, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:368, (c) the amino acid sequence of SEQ ID NO:155 (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:376; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203; and (f) HVR comprising the amino acid sequence of SEQ ID NO:231. -L3, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 369, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155, (d) ) HVR-L1 comprising the amino acid sequence of SEQ ID NO:378, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:394, (a) SEQ ID NO:90 (b) HVR-H2 containing the amino acid sequence of SEQ ID NO:370; (c) HVR-H3 containing the amino acid sequence of SEQ ID NO:155; (d) containing the amino acid sequence of SEQ ID NO:378 (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:394; (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:90; (b) the amino acid sequence of SEQ ID NO:371 (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 178; (e) HVR- comprising the amino acid sequence of SEQ ID NO: 203 L2, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:394, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:368, (c) (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 385; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 203; and (f) SEQ ID NO: 394. (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90; (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 368; (c) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 155 (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:378; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:395; (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 368, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:390; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:394; (a) the amino acid sequence of SEQ ID NO:90. (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 372; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155; (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 378 (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 391; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 394; (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90; HVR-H2 comprising the amino acid sequence of SEQ ID NO:368, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:375, (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:386, (e) the amino acid of SEQ ID NO:203 HVR-L2 comprising the sequence, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:394, (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:90, (b) HVR comprising the amino acid sequence of SEQ ID NO:368. -H2, (c) of SEQ ID NO: 155 (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:387; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203; and (f) the amino acid sequence of SEQ ID NO:394. Anti-MerTK antibody containing HVR-L3.

In another aspect, the anti-MerTK antibody comprises and 308, at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% of Includes heavy chain variable domain (V _H ) sequences with sequence identity. In certain embodiments, from SEQ. A V _H having at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to an amino acid sequence selected from the group consisting of The sequence contains substitutions (eg, conservative substitutions), insertions, or deletions relative to the reference sequence, but an anti-MerTK antibody containing that sequence retains the ability to bind MerTK. In certain embodiments, the , a total of 1-10 amino acids have been substituted, inserted and/or deleted. In certain embodiments, the , a total of 1-5 amino acids have been substituted, inserted and/or deleted. In certain embodiments, substitutions, insertions, or deletions occur in regions outside the HVR (ie, in the FRs). optionally, the anti-MerTK antibody is SEQ ID NO: 37, 290, 291, 292, 293, 294, 295, 296, 297, 298, 299, 300, 301, 302, 303, 304, 305, 306, 307, or 308 _VH sequences, including post-translational modifications of the sequences. In certain embodiments, said V _H is selected from the group consisting of (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:90, (b) SEQ ID NOs:122, 364, 365, 366, 367, and 368 1, 2, or 3 HVRs selected from HVR-H2 comprising an amino acid sequence, and (c) HVR-H3 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 155, 373, 374, and 375. including.

In another aspect, from SEQ ID NOs: 72, 309, 310, 311, 312, 313, 314, 315, 316, 316, 318, 319, 320, 321, 322, 323, 324, 325, 326, 327, and 328 at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% sequence identity to an amino acid sequence selected from the group of provides an anti-MerTK antibody comprising a light chain variable domain (V _L ) having a and has at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity to an amino acid sequence selected from the group consisting of 328 The _VL sequence contains substitutions (eg, conservative substitutions), insertions, or deletions relative to the reference sequence, but anti-MerTK antibodies containing that sequence retain the ability to bind MerTK. In some embodiments, SEQ ID NO: 72, 309, 310, 311, 312, 313, 314, 315, 316, 316, 318, 319, 320, 321, 322, 323, 324, 325, 326, 327, or 328, a total of 1-10 amino acids have been substituted, inserted and/or deleted. In certain embodiments, SEQ ID NO: 72, 309, 310, 311, 312, 313, 314, 315, 316, 316, 318, 319, 320, 321, 322, 323, 324, 325, 326, 327, or 328, a total of 1-5 amino acids have been substituted, inserted and/or deleted. In certain embodiments, the substitution, insertion, or deletion occurs in regions outside the HVR (ie, in the FRs). Optionally, said anti-MerTK antibody is SEQ ID NO: 72, 309, 310, 311, 312, 313, 314, 315, 316, 316, 318, 319, 320, 321, 322, 323, 324, 325, 326, 327 , or 328 V _L sequences, including post-translational modifications of the sequences. In certain embodiments, said V _L is (a) an amino acid selected from the group consisting of (b) HVR-L2 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 203, 388, 389, 390, and 391; and (c) SEQ ID NOs: 231, 392, 393, and 1, 2 or 3 HVRs selected from HVR-L3 comprising an amino acid sequence selected from the group consisting of 394.

In some embodiments, an anti-MerTK antibody is provided comprising a V _H of any of the above embodiments and a V _L of any of the above embodiments. In some embodiments, provided herein is an anti-MerTK antibody comprising the V _H of any of the above embodiments and the V _L of any of the above embodiments. In one embodiment, the antibody comprises SEQ ID NOs: 37, 290, 291, 292, 293, 294, 295, 296, 297, 298, 299, 300, 301, 302, 303, 304, 305, 306, respectively, 307, and 308 and of Includes _VH and _VL sequences, including post-translational modifications of those sequences.

In some embodiments, provided herein is an anti-MerTK antibody comprising a heavy chain variable domain (V _H ) and a light chain variable domain (V _L ), wherein the V _H and V _L are defined as follows: is selected from the group consisting of: VH comprising the amino acid sequence of SEQ ID NO:37 and _VL comprising the amino acid sequence of SEQ ID NO:72, _VH comprising the amino acid sequence of SEQ ID NO:290 and _V comprising the amino acid sequence of SEQ ID NO:309 _L , VH comprising the amino acid sequence of SEQ ID NO:291 and VL comprising the amino acid sequence of SEQ ID NO _: 310, _VH comprising the amino acid sequence of SEQ ID NO:292 and _VL comprising the amino acid sequence of SEQ ID NO:311, _SEQ ID NO:293 V _H containing the amino acid sequence and V L containing the amino acid sequence of SEQ ID NO: 312, V _H containing the amino acid sequence of SEQ ID NO: 294 and V _L containing _the amino acid sequence of SEQ ID NO: 313, V _H containing the amino acid sequence of SEQ ID NO: 295 and V _L comprising the amino acid sequence of SEQ ID NO: 314, V _H comprising the amino acid sequence of SEQ ID NO: 296 and V _L comprising the amino acid sequence of SEQ ID NO: 315, V _H comprising the amino acid sequence of SEQ ID NO: 290 and the amino acids of SEQ ID NO: 316 V _L comprising the sequence, V _H comprising the amino acid sequence of SEQ ID NO:297 and V _L comprising the amino acid sequence of SEQ ID NO:317, V _H comprising the amino acid sequence of SEQ ID NO:298 and V _L comprising the amino acid sequence of SEQ ID NO:318, V H containing the amino acid sequence of SEQ ID NO: 292 and V _L containing the amino acid sequence of SEQ ID NO: 319, V _H containing the amino acid sequence of SEQ ID NO: 299 and V _L containing the amino acid sequence of SEQ ID NO: 320 _, the amino acid sequence of SEQ ID NO: 300 and a V _L comprising the amino acid sequence of SEQ ID NO: 311, a V _H comprising the amino acid sequence of SEQ ID NO: 301 and a V _L comprising the amino acid sequence of SEQ ID NO _: 321, a V _H comprising the amino acid sequence of SEQ ID NO: 302 and the sequence V _L containing the amino acid sequence of SEQ ID NO: 322, V _H containing the amino acid sequence of SEQ ID NO: 303 and V _L containing the amino acid sequence of SEQ ID NO: 311, V _H containing the amino acid sequence of SEQ ID NO: 304 and the amino acid sequence of SEQ ID NO: 322 V _L comprising the amino acid sequence of SEQ ID NO: 305 and V _L comprising the amino acid sequence of SEQ ID NO: 322, V _H comprising the amino _{acid sequence of SEQ ID NO: 301 and V L comprising} the amino acid sequence of SEQ ID NO: 323, SEQ ID NO: _VH comprising 301 amino acid sequences and SEQ ID NO:3 V _L comprising the amino acid sequence of 24 amino acids, V _H comprising the amino acid sequence of SEQ ID NO:301 and V _L comprising the amino acid sequence of SEQ ID NO:325, V _H comprising the amino acid sequence of SEQ ID NO:306 and the amino acid sequence of SEQ ID NO:326 V _L , V _H comprising the amino acid sequence of SEQ ID NO:307 and V _{L comprising the amino acid sequence of SEQ ID NO:327, and V H comprising} the amino acid sequence of SEQ ID NO:308 and V _L comprising the amino acid sequence of SEQ ID NO:328.

In some embodiments, the anti-MerTK antibodies of the present disclosure bind to MerTK, thus MTK-01, MTK-02, MTK-03, MTK-04, MTK-05, MTK-06, MTK-07, -08, MTK-09, MTK-10, MTK-11, MTK-12, MTK-13, MTK-14, MTK-15 (MTK-15.1, MTK-15.2, MTK-15.3, MTK-15.3 -15.4, MTK-15.5, MTK-15.6, MTK-15.7, MTK-15.8, MTK-15.9, MTK-15.10, MTK-15.11, MTK-15 .12, including MTK-15.13, MTK-15.14, and MTK-15.15), MTK-16 (including MTK-16.1 and MTK-16.2), MTK-17, MTK- 18, MTK-19, MTK-20, MTK-21, MTK-22, MTK-23, MTK-24, MTK-25, MTK-26, MTK-27, MTK-28, MTK-29 (MTK-29. 1, MTK-29.2, MTK-29.3, MTK-29.4, MTK-29.5, MTK-29.6, MTK-29.7, MTK-29.8, MTK-29.9, MTK-29.10, MTK-29.11, MTK-29.12, MTK-29.13, MTK-29.14, MTK-29.15, MTK-29.16, MTK-29.17, MTK- 29.18, MTK-29.19, MTK-29.20, and MTK-29.21), MTK-30, MTK-31, MTK-32, MTK-33 (including MTK-33.1, MTK- 33.2, MTK-33.3, MTK-33.4, MTK-33.5, MTK-33.6, MTK-33.7, MTK-33.8, MTK-33.9, MTK-33. 10, MTK-33.11, MTK-33.12, MTK-33.13, MTK-33.14, MTK-33.15, MTK-33.16, MTK-33.17, MTK-33.18, MTK-33.19, MTK-33.20, MTK-33.21, MTK-33.22, MTK-33.23, and MTK-33.24), MTK-34, MTK-35, and MTK -36, as well as any combination thereof, competitively inhibits binding of at least one reference antibody.

In some embodiments, the anti-MerTK antibodies of the disclosure are MTK-01, MTK-02, MTK-03, MTK-04, MTK-05, MTK-06, MTK-07, MTK-08, MTK-09 , MTK-10, MTK-11, MTK-12, MTK-13, MTK-14, MTK-15 (MTK-15.1, MTK-15.2, MTK-15.3, MTK-15.4, MTK -15.5, MTK-15.6, MTK-15.7, MTK-15.8, MTK-15.9, MTK-15.10, MTK-15.11, MTK-15.12, MTK-15 .13, MTK-15.14, and MTK-15.15), MTK-16 (including MTK-16.1 and MTK-16.2), MTK-17, MTK-18, MTK-19, MTK-20, MTK-21, MTK-22, MTK-23, MTK-24, MTK-25, MTK-26, MTK-27, MTK-28, MTK-29 (MTK-29.1, MTK-29. 2, MTK-29.3, MTK-29.4, MTK-29.5, MTK-29.6, MTK-29.7, MTK-29.8, MTK-29.9, MTK-29.10, MTK-29.11, MTK-29.12, MTK-29.13, MTK-29.14, MTK-29.15, MTK-29.16, MTK-29.17, MTK-29.18, MTK- 29.19, MTK-29.20, and MTK-29.21), MTK-30, MTK-31, MTK-32, MTK-33 (MTK-33.1, MTK-33.2, MTK- 33.3, MTK-33.4, MTK-33.5, MTK-33.6, MTK-33.7, MTK-33.8, MTK-33.9, MTK-33.10, MTK-33. 11, MTK-33.12, MTK-33.13, MTK-33.14, MTK-33.15, MTK-33.16, MTK-33.17, MTK-33.18, MTK-33.19, MTK-33.20, MTK-33.21, MTK-33.22, MTK-33.23, and MTK-33.24), MTK-34, MTK-35, and MTK-36 Binds an epitope of MerTK that is the same as or overlaps with an epitope of human MerTK that is bound by at least one reference antibody. Detailed exemplary methods for mapping epitopes bound by antibodies are described by Morris (1996) "Epitope Mapping Protocols," in Methods in Molecular Biology vol. 66 (Humana Press, Totowa, NJ).

In some embodiments, an anti-MerTK antibody of the present disclosure competitively inhibits binding of at least one reference antibody or overlaps with an epitope of human MerTK bound by at least one reference antibody The reference antibody is an anti-MerTK antibody that binds to an epitope of MerTK and comprises a heavy chain variable domain ( _VH ) and a light chain variable domain ( _VL ), wherein the _VH and _VL are the group consisting of is selected from: a VH comprising the amino acid sequence of SEQ ID NO:5 and _{a VL} comprising the amino acid sequence of SEQ ID NO:40, a _VH comprising the amino acid sequence of SEQ ID NO:6 and a _VL comprising the amino acid sequence of SEQ ID NO:41 _, a sequence VH containing the amino acid sequence of SEQ ID NO: 7 and _VL containing the amino acid sequence of SEQ ID NO: 42, _VH containing the amino acid sequence of SEQ ID NO: 8 and _VL containing the amino acid sequence of SEQ ID NO: 43, _and the amino acid sequence of SEQ ID NO: 9 V _H containing the amino acid sequence of SEQ ID NO: 44 and V _L containing the amino acid sequence of SEQ ID NO: 44, V _H containing the amino acid sequence of SEQ ID NO: 10 and V _L containing the amino acid sequence of SEQ ID NO: 45, V _H containing the amino acid sequence of SEQ ID NO: 11 and SEQ ID NO: 46 amino acid sequence, _VH comprising the amino acid sequence of SEQ ID NO: ₁₂ and _VL comprising the amino acid sequence of SEQ ID NO: 47, _VH comprising the amino acid sequence of SEQ ID NO: 13 and the amino acid sequence of SEQ ID NO: 48. V _L , V H containing the amino acid sequence of SEQ ID NO: 14 and V _L containing the amino acid sequence of SEQ ID NO: 49 _{, V H containing the amino acid sequence of SEQ ID NO: 15 and V L containing the} amino acid sequence of SEQ ID NO: 50, SEQ ID NO: 16 and V _{L containing the amino acid sequence of SEQ ID NO: 51, V H containing the amino acid sequence of SEQ ID NO: 17 and V L containing} the amino acid sequence of SEQ ID NO: 52, V containing the amino acid sequence of SEQ ID NO: 18 _H and VL comprising the amino acid sequence of SEQ ID NO:53, _VH comprising the amino acid sequence of SEQ ID NO _: 19 and _VL comprising the amino acid sequence of SEQ ID NO:54, _VH comprising the amino acid sequence of SEQ ID NO:20 and SEQ ID NO:55 V _L containing the amino acid sequence, V _H containing the amino acid sequence of SEQ ID NO: 21 and V L containing the amino acid sequence of SEQ ID NO: 56, V _H containing _{the amino acid sequence of SEQ ID NO: 22 and V L containing} the amino acid sequence of SEQ ID NO: 57 , _VH comprising the amino acid sequence of SEQ ID NO:23 and _VL comprising the amino acid sequence of SEQ ID NO:58, the amino acid of SEQ ID NO:24 VH containing the amino acid sequence and _VL containing the amino acid sequence of SEQ ID NO: 59, _VH containing the amino acid sequence of SEQ ID NO: 25 and _VL containing the amino acid sequence of SEQ ID NO: 60, _V containing the amino acid sequence of SEQ ID NO: 26 _H and VL comprising the amino acid sequence of SEQ ID _NO : 61, V _H comprising the amino acid sequence of SEQ ID NO: 27 and _VL comprising the amino acid sequence of SEQ ID NO: 62, V _H comprising the amino acid sequence of SEQ ID NO: 28 and SEQ ID NO: 63 V _L containing the amino acid sequence, V _H containing the amino acid sequence of SEQ ID NO: 29 and V _{L containing the amino acid sequence of SEQ ID NO: 64, V H containing the amino acid sequence of SEQ ID NO: 30 and V L containing the} amino acid sequence of SEQ ID NO: 65 , V _H containing the amino acid sequence of SEQ ID NO: 31 and V _L containing the amino acid sequence of SEQ ID NO: 66, V _H containing the amino acid sequence of SEQ ID NO: 32 and V _L containing the amino acid sequence of SEQ ID NO: 67, the amino acid of SEQ ID NO: 33 V _H containing the sequence and V _L containing the amino acid sequence of SEQ ID NO: 68, V _H containing the amino acid sequence of SEQ ID NO: 34 and V _L containing the amino acid sequence of SEQ ID NO: 69, V _H containing the amino acid sequence of SEQ ID NO: 35 and V _{L containing the amino acid sequence of SEQ ID NO: 70, V H} containing the amino acid sequence of SEQ ID NO: 36 and V _L containing the amino acid sequence _{of SEQ ID NO: 71, V H containing} the amino acid sequence of SEQ ID NO: 37 and the amino acid sequence of SEQ ID NO: 72 , a V _H comprising the amino acid sequence of SEQ ID NO:38 and a V _L comprising the amino acid sequence of SEQ ID NO:73 _{, and a V H comprising the amino acid sequence of SEQ ID NO:39 and a V L comprising the} amino acid sequence of SEQ ID NO:74.

In some embodiments, an anti-MerTK antibody of this disclosure has the variable heavy chain amino acid sequence of SEQ ID NOs: 234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, or 246; and a full length heavy chain amino acid sequence comprising a heavy chain Fc selected from the group consisting of: and a full-length light chain amino acid sequence comprising a light chain Fc comprising the amino acid sequence of SEQ ID NO:412.

In some embodiments, the anti-MerTK antibody of the present disclosure comprises a variable heavy chain amino acid sequence of SEQ ID NOs:255 or 256, and a full-length heavy chain Fc selected from the group consisting of SEQ ID NOs:396-411 A full length light chain amino acid sequence comprising a variable light chain amino acid sequence of SEQ ID NO:257 or 258 and a light chain Fc comprising the amino acid sequence of SEQ ID NO:412.

In some embodiments, an anti-MerTK antibody of this disclosure has the full-length heavy chain amino acid sequence of SEQ ID NO:413, 414, 415, 416, 417, 418, 419, or 420 and the full-length light chain amino acid sequence of SEQ ID NO:421 Contains arrays. Thus, in some embodiments, the anti-MerTK antibody comprises the heavy chain amino acid sequence of SEQ ID NO:413 and the light chain amino acid sequence of SEQ ID NO:421, the heavy chain amino acid sequence of SEQ ID NO:414 and the light chain amino acid sequence of SEQ ID NO:421, heavy chain amino acid sequence of SEQ ID NO:415 and light chain amino acid sequence of SEQ ID NO:421, heavy chain amino acid sequence of SEQ ID NO:416 and light chain amino acid sequence of SEQ ID NO:421, heavy chain amino acid sequence of SEQ ID NO:417 and light chain amino acid sequence of SEQ ID NO:421 chain amino acid sequence, the heavy chain amino acid sequence of SEQ ID NO:418 and the light chain amino acid sequence of SEQ ID NO:421, the heavy chain amino acid sequence of SEQ ID NO:419 and the light chain amino acid sequence of SEQ ID NO:421, or the heavy chain amino acid sequence of SEQ ID NO:420 and It contains the light chain amino acid sequence of SEQ ID NO:421.

In some embodiments, an anti-MerTK antibody of this disclosure has the full-length heavy chain amino acid sequence of SEQ ID NO: 422, 423, 424, 425, 426, 427, 428, or 429 and the full-length light chain amino acid sequence of SEQ ID NO: 430 Contains arrays. Thus, in some embodiments, the anti-MerTK antibody comprises the heavy chain amino acid sequence of SEQ ID NO:422 and the light chain amino acid sequence of SEQ ID NO:430, the heavy chain amino acid sequence of SEQ ID NO:423 and the light chain amino acid sequence of SEQ ID NO:430, heavy chain amino acid sequence of SEQ ID NO:424 and light chain amino acid sequence of SEQ ID NO:430, heavy chain amino acid sequence of SEQ ID NO:425 and light chain amino acid sequence of SEQ ID NO:430, heavy chain amino acid sequence of SEQ ID NO:426 and light chain amino acid sequence of SEQ ID NO:430 chain amino acid sequence, the heavy chain amino acid sequence of SEQ ID NO:427 and the light chain amino acid sequence of SEQ ID NO:430, the heavy chain amino acid sequence of SEQ ID NO:428 and the light chain amino acid sequence of SEQ ID NO:430, or the heavy chain amino acid sequence of SEQ ID NO:429 and It contains the light chain amino acid sequence of SEQ ID NO:430.

In some embodiments, an anti-MerTK antibody of this disclosure has a variable weight SEQ ID NOs: 274, 275, 276, 277, 278, 279, 280, 281; 282, 283, 284, 285, 286, 287, 288, or 289 variable light chain amino acid sequences and a full length light chain amino acid sequence comprising a light chain Fc comprising the amino acid sequence of SEQ ID NO:412.

In some embodiments, the anti-MerTK antibodies of this disclosure are , 307, or 308, and a full-length heavy chain amino acid sequence comprising a heavy chain Fc selected from the group consisting of SEQ ID NOs: 396-411; a light chain comprising the variable light chain amino acid sequence of 313, 314, 315, 316, 317, 318, 319, 320, 321, 322, 323, 324, 325, 326, 327, or 328 and the amino acid sequence of SEQ ID NO: 412 Includes full length light chain amino acid sequence including Fc.

In some embodiments, an anti-MerTK antibody of this disclosure has the full-length heavy chain amino acid sequence of SEQ ID NO:431, 432, 433, 434, 435, 436, 437, or 438 and the full-length light chain amino acid sequence of SEQ ID NO:439 Contains arrays. Thus, in some embodiments, the anti-MerTK antibody comprises the heavy chain amino acid sequence of SEQ ID NO:431 and the light chain amino acid sequence of SEQ ID NO:439, the heavy chain amino acid sequence of SEQ ID NO:432 and the light chain amino acid sequence of SEQ ID NO:439, heavy chain amino acid sequence of SEQ ID NO:433 and light chain amino acid sequence of SEQ ID NO:439; heavy chain amino acid sequence of SEQ ID NO:434 and light chain amino acid sequence of SEQ ID NO:439; chain amino acid sequence, the heavy chain amino acid sequence of SEQ ID NO:436 and the light chain amino acid sequence of SEQ ID NO:439, the heavy chain amino acid sequence of SEQ ID NO:437 and the light chain amino acid sequence of SEQ ID NO:439, or the heavy chain amino acid sequence of SEQ ID NO:438 and It contains the light chain amino acid sequence of SEQ ID NO:439.

In some embodiments, the anti-MerTK antibodies of this disclosure have the full-length heavy chain amino acid sequences of SEQ ID NOs:464, 465, 466, 467, 468, 469, 470, and 471 and the full-length light chain amino acid sequences of SEQ ID NO:472 Contains arrays. Thus, in some embodiments, the anti-MerTK antibody comprises the heavy chain amino acid sequence of SEQ ID NO:464 and the light chain amino acid sequence of SEQ ID NO:472, the heavy chain amino acid sequence of SEQ ID NO:465 and the light chain amino acid sequence of SEQ ID NO:472, heavy chain amino acid sequence of SEQ ID NO:466 and light chain amino acid sequence of SEQ ID NO:472; heavy chain amino acid sequence of SEQ ID NO:467 and light chain amino acid sequence of SEQ ID NO:472; the heavy chain amino acid sequence of SEQ ID NO:469 and the light chain amino acid sequence of SEQ ID NO:472, the heavy chain amino acid sequence of SEQ ID NO:470 and the light chain amino acid sequence of SEQ ID NO:472, or the heavy chain amino acid sequence of SEQ ID NO:471 and It contains the light chain amino acid sequence of SEQ ID NO:472.

In some embodiments, an anti-MerTK antibody of this disclosure has the full-length heavy chain amino acid sequence of SEQ ID NO:440, 441, 442, 443, 444, 445, 446, or 447 and the full-length light chain amino acid sequence of SEQ ID NO:448 Contains arrays. Thus, in some embodiments, the anti-MerTK antibody comprises the heavy chain amino acid sequence of SEQ ID NO:440 and the light chain amino acid sequence of SEQ ID NO:448, the heavy chain amino acid sequence of SEQ ID NO:441 and the light chain amino acid sequence of SEQ ID NO:448, heavy chain amino acid sequence of SEQ ID NO:442 and light chain amino acid sequence of SEQ ID NO:448, heavy chain amino acid sequence of SEQ ID NO:443 and light chain amino acid sequence of SEQ ID NO:448, heavy chain amino acid sequence of SEQ ID NO:444 and light chain amino acid sequence of SEQ ID NO:448 chain amino acid sequence, the heavy chain amino acid sequence of SEQ ID NO:445 and the light chain amino acid sequence of SEQ ID NO:448, the heavy chain amino acid sequence of SEQ ID NO:446 and the light chain amino acid sequence of SEQ ID NO:448, or the heavy chain amino acid sequence of SEQ ID NO:447 and It contains the light chain amino acid sequence of SEQ ID NO:448.

In some embodiments, an anti-MerTK antibody of the present disclosure competitively inhibits binding of at least one reference antibody or overlaps with an epitope of human MerTK bound by at least one reference antibody The reference antibody is an anti-MerTK antibody that binds to an epitope of MerTK and comprises a heavy chain variable domain ( _VH ) and a light chain variable domain ( _VL ), wherein the _VH and _VL are the group consisting of a VH comprising the amino acid sequence of SEQ ID NO: 19 and a V _L comprising the amino acid sequence of SEQ ID NO: _{54, a V H comprising the amino acid sequence of SEQ ID NO: 234 and a V L comprising the} amino acid sequence of SEQ ID NO: 247, sequences VH comprising the amino acid sequence of SEQ ID NO:235 and _VL comprising the amino acid sequence of SEQ ID NO:247, _VH comprising the amino acid sequence of SEQ ID NO:236 and _VL comprising the amino acid sequence of SEQ ID NO:248, and _the amino acid sequence of SEQ ID NO:236 and a V _L comprising the amino acid sequence of SEQ ID NO:249, a V _H comprising the amino acid sequence of SEQ ID NO:237 and a V _L comprising the amino acid sequence of SEQ ID NO:249, a V _H comprising the amino acid sequence of SEQ ID NO:238 _and SEQ ID NO: V _L comprising the amino acid sequence of SEQ ID NO: 249, V _{H comprising the amino acid sequence of SEQ ID NO: 239 and V L comprising the amino acid sequence of SEQ ID NO: 250, V H comprising} the amino acid sequence of SEQ ID NO: 240 and the amino acid sequence of SEQ ID NO: 251 _VL , VH comprising the amino acid sequence of SEQ ID NO:241 and VL comprising the amino acid sequence of SEQ ID NO:252, _VH comprising the amino acid sequence of SEQ ID NO:242 and _VL comprising the amino acid sequence of SEQ ID NO:249 _, SEQ _ID NO:243 and V _L containing the amino acid sequence of SEQ ID NO: 247, V _{H containing the amino acid sequence of SEQ ID NO: 244 and V L containing} the amino acid sequence of SEQ ID NO: 251, V containing the amino acid sequence of SEQ ID NO: 245 _H and VL _comprising the amino acid sequence of SEQ ID NO:253, _VH comprising the amino acid sequence of SEQ ID NO:246 and _VL comprising the amino acid sequence of SEQ ID NO:247, and _VH comprising the amino acid sequence of SEQ ID NO:246 and SEQ ID NO:254 A V _L comprising the amino acid sequence of .

In some embodiments, an anti-MerTK antibody of the present disclosure competitively inhibits binding of at least one reference antibody or overlaps with an epitope of human MerTK bound by at least one reference antibody The reference antibody is an anti-MerTK antibody that binds to an epitope of MerTK and comprises a heavy chain variable domain ( _VH ) and a light chain variable domain ( _VL ), wherein the _VH and _VL are the group consisting of is selected from: a V _H comprising the amino acid sequence of SEQ ID NO:20 and a V _L comprising the amino acid sequence of SEQ ID NO:55, a V _H comprising the amino acid sequence of SEQ ID NO:255 and a V _L comprising the amino acid sequence of SEQ ID NO:257; A V _H comprising the amino acid sequence of SEQ ID NO:256 and a V _L comprising the amino acid sequence of SEQ ID NO:258.

In some embodiments, an anti-MerTK antibody of the present disclosure competitively inhibits binding of at least one reference antibody or overlaps with an epitope of human MerTK bound by at least one reference antibody The reference antibody is an anti-MerTK antibody that binds to an epitope of MerTK and comprises a heavy chain variable domain ( _VH ) and a light chain variable domain ( _VL ), wherein the _VH and _VL are the group consisting of a VH comprising the amino acid sequence of SEQ ID NO: 33 and a V _L comprising the amino acid sequence of SEQ ID NO: 68 _{, a V H comprising the amino acid sequence of SEQ ID NO: 259 and a V L comprising the} amino acid sequence of SEQ ID NO: 274, sequences VH comprising the amino acid sequence of SEQ ID NO:260 and _VL comprising the amino acid sequence of SEQ ID NO:275, _VH comprising the amino acid sequence of SEQ ID NO:261 and _VL comprising the amino acid sequence of SEQ ID NO:276, _and the amino acid sequence of SEQ ID NO:262 V _H comprising the amino acid sequence of SEQ ID NO: 277 and V _L comprising the amino acid sequence of SEQ ID NO: 277, V _H comprising the amino acid sequence of SEQ ID NO: 263 and V _L comprising the amino acid sequence of SEQ ID NO: 277, V _H comprising the amino acid sequence of SEQ ID NO: 264 and SEQ ID NO: 277 amino acid sequence, _VH comprising the amino acid sequence of SEQ ID NO _: 265 and _VL comprising the amino acid sequence of SEQ ID NO:277, _VH comprising the amino acid sequence of SEQ ID NO:266 and SEQ ID NO:277 _VL , VH comprising the amino acid sequence of SEQ ID NO:267 and VL comprising the amino acid sequence of SEQ ID NO:278, _VH comprising the amino acid sequence of SEQ ID NO:268 and _VL comprising the amino acid sequence of SEQ ID NO:279 _, SEQ ID NO _: 269 and V _{L containing the amino acid sequence of SEQ ID NO: 279, V H containing the amino acid sequence of SEQ ID NO: 264 and V L containing} the amino acid sequence of SEQ ID NO: 280, V containing the amino acid sequence of SEQ ID NO: 270 _H and VL comprising the amino acid sequence of SEQ ID _{NO:281, VH comprising the amino acid sequence of SEQ ID NO:265 and VL comprising the amino acid sequence of SEQ ID NO:282, VH comprising the amino} acid sequence of SEQ ID NO:264 and SEQ ID NO:283 V _L comprising the amino acid sequence, V _H comprising the amino acid sequence of SEQ ID NO: 271 and V _L comprising the amino acid sequence of SEQ ID NO: 284, V _H comprising the amino acid sequence of SEQ ID NO: 272 and V _L comprising the amino acid sequence of SEQ ID NO: 285 , the amino acids of SEQ ID NO:271 V _H comprising the sequence and V _L comprising the amino acid sequence of SEQ ID NO: 286, V _H comprising the amino acid sequence of SEQ ID NO: 273 and V _L comprising the amino acid sequence of SEQ ID NO: 287, V _H comprising the amino acid sequence of SEQ ID NO: 273 and A V _L comprising the amino acid sequence of SEQ ID NO:288, and a V _H comprising the amino acid sequence of SEQ ID NO:273 and a V _L comprising the amino acid sequence of SEQ ID NO:289.

In some embodiments, an anti-MerTK antibody of the present disclosure competitively inhibits binding of at least one reference antibody or overlaps with an epitope of human MerTK bound by at least one reference antibody The reference antibody is an anti-MerTK antibody that binds to an epitope of MerTK and comprises a heavy chain variable domain ( _VH ) and a light chain variable domain ( _VL ), wherein the _VH and _VL are the group consisting of is selected from: VH comprising the amino acid sequence of SEQ ID NO:37 and _VL comprising the amino acid sequence of SEQ ID NO:72, _VH comprising the amino acid sequence of SEQ ID NO:290 and _VL comprising the amino acid sequence of SEQ _ID NO:309, sequences VH comprising the amino acid sequence of SEQ ID NO: 291 and _VL comprising the amino acid sequence of SEQ ID NO: 310, VH comprising the amino acid sequence of SEQ ID NO: 292 and _VL comprising the amino acid sequence of SEQ ID NO: 311 _{, and} the amino acid sequence of SEQ ID NO: 293 V _H comprising the amino acid sequence of SEQ ID NO: 312 and V _L comprising the amino acid sequence of SEQ ID NO: 312, V _H comprising the amino acid sequence of SEQ ID NO: 294 and V _L comprising the amino acid sequence of SEQ ID NO: 313, V _H comprising the amino acid sequence of SEQ ID NO: 295 and SEQ ID NO: 314 amino acid sequence, _VH comprising the amino acid sequence of SEQ ID NO: ₂₉₆ and _VL comprising the amino acid sequence of SEQ ID NO:315, _VH comprising the amino acid sequence of SEQ ID NO:290 and SEQ ID NO:316 _VL , VH comprising the amino acid sequence of SEQ ID NO:297 and VL comprising the amino acid sequence of SEQ ID NO:317, _VH comprising the amino acid sequence of SEQ ID NO:298 and _VL comprising the amino acid sequence of SEQ ID NO:318 _{, SEQ} ID NO:292 and V _{L containing the amino acid sequence of SEQ ID NO: 319, V H containing the} amino acid sequence of SEQ ID NO: 299 and V _L containing the amino acid sequence of SEQ ID NO: 320, V containing the amino acid sequence of SEQ ID NO: 300 _H and VL _comprising the amino acid sequence of SEQ ID NO:311, _VH comprising the amino acid sequence of SEQ ID NO:301 and _VL comprising the amino acid sequence of SEQ ID NO:321, _VH comprising the amino acid sequence of SEQ ID NO:302 and SEQ ID NO:322 V _L comprising the amino acid sequence, V _H comprising the amino acid sequence of SEQ ID NO: 303 and V _L comprising the amino acid sequence of SEQ ID NO: 311, V _H comprising the amino acid sequence of SEQ ID NO: 304 and V _L comprising the amino acid sequence of SEQ ID NO: 322 , the amino acids of SEQ ID NO:305 V _H containing the sequence and V _L containing the amino acid sequence of SEQ ID NO: 322, V _H containing the amino acid sequence of SEQ ID NO: 301 and V _L containing the amino acid sequence of SEQ ID NO: 323, V _H containing the amino acid sequence of SEQ ID NO: 301 and VL comprising the amino acid sequence of SEQ ID NO:324, _VH comprising the amino acid sequence of SEQ ID NO:301 _{and VL} comprising the amino acid sequence of SEQ ID NO:325, _VH comprising the amino acid sequence of SEQ ID NO:306 and the amino acid sequence of SEQ ID NO:326 , _VH comprising the amino acid sequence of SEQ ID _NO :307 and _VL comprising the amino acid sequence of SEQ ID NO:327, and _VH comprising the amino acid sequence of SEQ ID NO:308 and _VL comprising the amino acid sequence of SEQ ID NO:328.

In some embodiments, the anti-MerTK antibody of the present disclosure comprises (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:368, (c) SEQ ID NO: (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:383; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203; and (f) the amino acid sequence of SEQ ID NO:232. including HVR-L3 containing In some embodiments, an anti-MerTK antibody of the present disclosure comprises a heavy chain variable domain (V _H ) and a light chain variable domain (V _L ), said V _H comprising the amino acid sequence of SEQ ID NO: 298, said _VL comprises the amino acid sequence of SEQ ID NO:318. In some embodiments, an anti-MerTK antibody of the disclosure comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence of SEQ ID NO:464 and the light chain comprises the amino acid sequence of SEQ ID NO:472 . In some embodiments, an anti-MerTK antibody of the disclosure comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence of SEQ ID NO:465 and the light chain comprises the amino acid sequence of SEQ ID NO:472 . In some embodiments, an anti-MerTK antibody of the disclosure comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence of SEQ ID NO:466 and the light chain comprises the amino acid sequence of SEQ ID NO:472 . In some embodiments, an anti-MerTK antibody of the disclosure comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence of SEQ ID NO:467 and the light chain comprises the amino acid sequence of SEQ ID NO:472 . In some embodiments, an anti-MerTK antibody of the disclosure comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence of SEQ ID NO:468 and the light chain comprises the amino acid sequence of SEQ ID NO:472 . In some embodiments, an anti-MerTK antibody of the disclosure comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence of SEQ ID NO:469 and the light chain comprises the amino acid sequence of SEQ ID NO:472 .

In some embodiments, the anti-MerTK antibody of the present disclosure comprises (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:84, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:99, (c) SEQ ID NO: (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:345; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:195; and (f) the amino acid sequence of SEQ ID NO:219. including HVR-L3 containing In some embodiments, an anti-MerTK antibody of the present disclosure comprises a heavy chain variable domain (V _H ) and a light chain variable domain (V _L ), said V _H comprising the amino acid sequence of SEQ ID NO: 256, said _VL comprises the amino acid sequence of SEQ ID NO:258. In some embodiments, an anti-MerTK antibody of the disclosure comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence of SEQ ID NO:422 and the light chain comprises the amino acid sequence of SEQ ID NO:430 . In some embodiments, an anti-MerTK antibody of the disclosure comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence of SEQ ID NO:423 and the light chain comprises the amino acid sequence of SEQ ID NO:430 . In some embodiments, an anti-MerTK antibody of the disclosure comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence of SEQ ID NO:424 and the light chain comprises the amino acid sequence of SEQ ID NO:430 . In some embodiments, an anti-MerTK antibody of the disclosure comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence of SEQ ID NO:425 and the light chain comprises the amino acid sequence of SEQ ID NO:430 . In some embodiments, an anti-MerTK antibody of the disclosure comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence of SEQ ID NO:426 and the light chain comprises the amino acid sequence of SEQ ID NO:430 . In some embodiments, an anti-MerTK antibody of the disclosure comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence of SEQ ID NO:427 and the light chain comprises the amino acid sequence of SEQ ID NO:430 .

In some embodiments, the anti-MerTK antibody of the present disclosure comprises (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:368, (c) SEQ ID NO: (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:376; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203; and (f) the amino acid sequence of SEQ ID NO:393. including HVR-L3 containing In some embodiments, an anti-MerTK antibody of the present disclosure comprises a heavy chain variable domain (V _H ) and a light chain variable domain (V _L ), said V _H comprising the amino acid sequence of SEQ ID NO:299, said _VL comprises the amino acid sequence of SEQ ID NO:320. In some embodiments, an anti-MerTK antibody of the disclosure comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence of SEQ ID NO:440 and the light chain comprises the amino acid sequence of SEQ ID NO:448 . In some embodiments, an anti-MerTK antibody of the disclosure comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence of SEQ ID NO:441 and the light chain comprises the amino acid sequence of SEQ ID NO:448 . In some embodiments, an anti-MerTK antibody of the disclosure comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence of SEQ ID NO:442 and the light chain comprises the amino acid sequence of SEQ ID NO:448 . In some embodiments, an anti-MerTK antibody of the disclosure comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence of SEQ ID NO:443 and the light chain comprises the amino acid sequence of SEQ ID NO:448 . In some embodiments, an anti-MerTK antibody of the disclosure comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence of SEQ ID NO:444 and the light chain comprises the amino acid sequence of SEQ ID NO:448 . In some embodiments, an anti-MerTK antibody of the disclosure comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence of SEQ ID NO:445 and the light chain comprises the amino acid sequence of SEQ ID NO:448 .

In some embodiments, the anti-MerTK antibody of the present disclosure comprises (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:84, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:329, (c) SEQ ID NO: (d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 169; (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 195; and (f) the amino acid sequence of SEQ ID NO: 219. including HVR-L3 containing In some embodiments, an anti-MerTK antibody of the present disclosure comprises a heavy chain variable domain (V _H ) and a light chain variable domain (V _L ), said V _H comprising the amino acid sequence of SEQ ID NO:225, said _VL comprises the amino acid sequence of SEQ ID NO:257. In some embodiments, an anti-MerTK antibody of the disclosure comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence of SEQ ID NO:413 and the light chain comprises the amino acid sequence of SEQ ID NO:421 . In some embodiments, an anti-MerTK antibody of the disclosure comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence of SEQ ID NO:414 and the light chain comprises the amino acid sequence of SEQ ID NO:421 . In some embodiments, an anti-MerTK antibody of the disclosure comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence of SEQ ID NO:415 and the light chain comprises the amino acid sequence of SEQ ID NO:421 . In some embodiments, an anti-MerTK antibody of the disclosure comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence of SEQ ID NO:416 and the light chain comprises the amino acid sequence of SEQ ID NO:421 . In some embodiments, an anti-MerTK antibody of the disclosure comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence of SEQ ID NO:417 and the light chain comprises the amino acid sequence of SEQ ID NO:421 . In some embodiments, an anti-MerTK antibody of the disclosure comprises a heavy chain and a light chain, wherein the heavy chain comprises the amino acid sequence of SEQ ID NO:418 and the light chain comprises the amino acid sequence of SEQ ID NO:421 .

In some embodiments, an anti-MerTK antibody of the disclosure binds to the extracellular domain (ECD) of human MerTK. In some embodiments, an anti-MerTK antibody of the disclosure binds to the N-terminal domain of human MerTK. In some embodiments, an anti-MerTK antibody of this disclosure binds to one or more amino acids within the amino acid sequence of SEQ ID NO:449. In some embodiments, the anti-MerTK antibodies of the present disclosure bind to immunoglobulin-like domain 1 (Ig1) of human MerTK. In some embodiments, an anti-MerTK antibody of this disclosure binds to one or more amino acid residues within the amino acid sequence of SEQ ID NO:450. In some embodiments, the anti-MerTK antibodies of the disclosure bind to immunoglobulin-like domain 2 (Ig2) of human MerTK. In some embodiments, an anti-MerTK antibody of this disclosure binds to one or more amino acid residues within the amino acid sequence of SEQ ID NO:451. In some embodiments, an anti-MerTK antibody of the present disclosure binds to fibronectin type III domain 1 (FN1) of human MerTK. In some embodiments, an anti-MerTK antibody of this disclosure binds to one or more amino acid residues within the amino acid sequence of SEQ ID NO:452. In some embodiments, an anti-MerTK antibody of the present disclosure binds to the juxtamembrane domain (JM) of human MerTK. In some embodiments, an anti-MerTK antibody of this disclosure binds to one or more amino acid residues within the amino acid sequence of SEQ ID NO:454. In some embodiments, an anti-MerTK antibody of the disclosure binds to the extracellular domain of the human MerTK protein, but not to the extracellular domain of the human Axl protein.

In some embodiments, an anti-MerTK antibody of the present disclosure binds to one or more domains within the extracellular domain of human MerTK. In some embodiments, the anti-MerTK antibodies of the present disclosure bind to immunoglobulin-like 1 domain 1 (Ig1) and fibronectin type III domain 1 (FN1) of human MerTK. In some embodiments, the anti-MerTK antibodies of the disclosure bind to immunoglobulin-like domain 2 (Ig2) and fibronectin type III domain 1 (FN1) of human MerTK.

In some embodiments, the anti-MerTK antibody according to any of the above embodiments is a monoclonal antibody, including humanized and/or human antibodies. In some embodiments, the anti-MerTK antibody is an antibody fragment, eg, an Fv, Fab, Fab', scFv, diabody, or F(ab')2 fragment. In some embodiments, the anti-MerTK antibody is a substantially full-length antibody, eg, an IgG1 antibody, IgG2a antibody, or other antibody class or isotype as defined herein.

In some embodiments, an anti-MerTK antibody according to any of the above embodiments may incorporate any of the features described in Sections 1-7 below, singly or in combination.

(1) Binding Affinity of Anti-MerTK Antibody In some embodiments of any of the antibodies provided herein, the antibody has a dissociation constant (K _D ) <1 μM, <100 nM, <10 nM, <1 nM, <0.1 nM, <0.01 nM, or <0.001 nM (eg, 10 ⁻⁸ M or less, such as 10 ⁻⁸ M to 10 ⁻¹³ M, such as 10 ⁻⁹ M to 10 ⁻¹³ M) . The dissociation constant can be determined by any biochemical or biophysical technique, such as ELISA, surface plasmon resonance (SPR), biolayer interferometry (eg Octet System by ForteBio), isothermal titration calorimetry (ITC), differential scanning. Identification can be via any analytical technique including calorimetry (DSC), circular dichroism (CD), stopped flow analysis, and colorimetric or fluorescent protein melting analysis. In one embodiment, Kd is measured by a radiolabeled antigen binding assay (RIA). In some embodiments, the RIA is performed using a Fab version of the antibody of interest and its antigen, for example, Chen et al. J. Mol. Biol. 293:865-881 (1999)). In some embodiments, the K _D is measured using a BIACORE surface plasmon resonance assay, e.g., an assay using a BIACORE-2000 or BIACORE-3000 (BIAcore, Inc., Piscataway, NJ) is measured at 25°C. at about 10 response units (RU) of immobilized antigen CM5 chip. In some embodiments, the K _D is identified using a monovalent antibody (eg, Fab) or full length antibody. In some embodiments, the K _D is identified using a monovalent form of a full-length antibody.

In some embodiments, an anti-MerTK antibody of the disclosure binds to human MerTK and has a K _D for binding to human MerTK of from about 1.4 nM to about 81 nM. In some embodiments, the anti-MerTK antibody binds to cynomolgus monkey MerTK and has a _KD for binding to cynomolgus monkey MerTK of from about 1.6 nM to about 107 nM. In some embodiments, an anti-MerTK antibody of the disclosure binds to murine MerTK and has a K _D for binding to murine MerTK of from about 30 nM to about 186M.

(2) Antibody Fragment In some embodiments of any of the antibodies provided herein, the antibody is an antibody fragment. Antibody fragments include, but are not limited to, Fab, Fab', Fab'-SH, F(ab') ₂ , Fv, and scFv fragments, as well as other fragments described below. For a review of certain antibody fragments, see Hudson et al. Nat. Med. 9:129-134 (2003). For a review of scFv fragments see, eg, WO93/16185, and US Pat. Nos. 5,571,894 and 5,587,458. See US Pat. No. 5,869,046 for a discussion of Fab and F(ab′) ₂ fragments with increased in vivo half-lives containing salvage receptor binding epitope residues.

Diabodies are antibody fragments with two antigen-binding sites that can be bivalent or bispecific. See for example EP404097, WO1993/01161, Hudson et al. , Nat. Med. 9:129-134 (2003). Triabodies and tetrabodies are also described in Hudson et al. Nat. Med. 9:129-134 (2003). Single domain antibodies are antibody fragments that contain all or part of the heavy chain variable domain or all or part of the light chain variable domain of an antibody. In certain embodiments, the single domain antibody is a human single domain antibody (see, eg, US Pat. No. 6,248,516).

Antibody fragments, as described herein, can be produced by a variety of techniques including, but not limited to, proteolysis of intact antibodies and production by recombinant host cells (eg, E. coli or phage).

(3) Chimeric and Humanized Antibodies In some embodiments of any of the antibodies provided herein, the antibody is a chimeric antibody. Certain chimeric antibodies are described, for example, in US Pat. No. 4,816,567. In one example, a chimeric antibody comprises a non-human variable region (eg, a variable region derived from a non-human primate such as mouse, rat, hamster, rabbit, or monkey) and a human constant region. In a further example, a chimeric antibody is a "class-switched" antibody in which the class or subclass has been altered from that of the parent antibody. Chimeric antibodies include antigen-binding fragments thereof.

In some embodiments of any of the antibodies provided herein, the antibody is a humanized antibody. Non-human antibodies are typically humanized to reduce their immunogenicity to humans while retaining the specificity and affinity of the parent non-human antibody. In certain embodiments, a humanized antibody is substantially non-immunogenic in humans. In certain embodiments, a humanized antibody has substantially the same affinity for a target as an antibody from another species from which the humanized antibody is derived. See, for example, US Pat. Nos. 5,530,101, 5,693,761, 5,693,762, and 5,585,089. In certain embodiments, amino acids of antibody variable domains are identified that can be altered to reduce their immunogenicity without reducing the affinity of the native antigen-binding domain. See, for example, US Pat. Nos. 5,766,886 and 5,869,619. Generally, a humanized antibody comprises one or more variable domains in which HVRs (or portions thereof) are derived from non-human antibodies and FRs (or portions thereof) are derived from human antibody sequences. A humanized antibody optionally also will comprise at least a portion of a human constant region. In some embodiments, some FR residues in a humanized antibody are replaced with non-human antibodies (e.g., antibodies from which HVR residues are derived), e.g., to restore or improve antibody specificity or affinity. is substituted with the corresponding residue from

Humanized antibodies and methods of making them are described, for example, in Almagro et al. Front. Biosci. 13:161 9-1633 (2008) and further described, for example, in US Pat. Human framework regions that can be used for humanization include, but are not limited to: framework regions selected using "best-fit" methods (e.g., Sims et 151:2296 (1993)), framework regions derived from the consensus sequences of human antibodies of particular subgroups of light or heavy chain variable regions (eg, Carter et al. Proc. Natl. USA, 89:4285 (1992), and Presta et al. J. Immunol. 151:2623 (1993)), human mature (somatically mutated) framework regions or human germline frameworks. regions (see, eg, Almagro and Fransson, Front. Biosci. 13:1619-1633 (2008)), as well as framework regions obtained from screening FR libraries (eg, Baca et al., J. Biol. Chem. 272: 10678-10684 (1997) and Rosok et al., J. Biol. Chem. 271:22611-22618 (1996)).

(4) Human Antibodies In some embodiments of any of the antibodies provided herein, the antibody is a human antibody. Human antibodies can be produced using various techniques known in the art. Human antibodies are generally described in van Dijk et al. Curr. Opin. Pharmacol. 5:368-74 (2001) and Lonberg Curr. Opin. Immunol. 20:450-459 (2008).

Human antibodies can be prepared by administering an immunogen to a transgenic animal that has been modified to produce intact human antibodies or intact antibodies comprising human variable regions in response to antigenic challenge. Mouse strains deficient in mouse antibody production can be engineered with large fragments of the human Ig loci in the hope that the mice will produce human antibodies to the exclusion of mouse antibodies. Large human Ig fragments are capable of maintaining a large variable genetic diversity as well as proper regulation of antibody production and expression. By exploiting the mouse mechanisms for antibody diversification and selection, as well as the lack of tolerance to human proteins, the human antibody repertoire recapitulated in these mouse strains can be directed against any antigen of interest, including human antigens. High affinity, fully human antibodies can be generated. Using hybridoma technology, antigen-specific human MAbs with the desired specificity can be produced and selected. Certain exemplary methods are described in US Pat. No. 5,545,807, EP 546,073, and EP 546,073. For example, US Pat. Nos. 6,075,181 and 6,150,584 describing XENOMOUSE™ technology, US Pat. No. 5,770,429 describing HUMAB® technology, and KM MOUSE® technology. See also U.S. Patent No. 7,041,870, which describes the VELOCIMOUSE® technology, and U.S. Patent Application Publication No. US 2007/0061900, which describes the VELOCIMOUSE® technology. Human variable regions from intact antibodies produced by such animals can be further modified, for example, by combining with a different human constant region.

Human antibodies can also be made by hybridoma-based methods. Human myeloma and mouse-human heteromyeloma cell lines for the production of human monoclonal antibodies have been described (eg, Kozbor J. Immunol. 133:3001 (1984) and Boerner et al. J. Immunol. 147:86). (1991)). Human antibodies generated through human B-cell hybridoma technology have also been described by Li et al. , Proc. Natl. Acad. Sci. USA, 103:3557-3562 (2006). Additional methods include, for example, those described in US Pat. No. 7,189,826, which describes the production of monoclonal human IgM antibodies from hybridoma cell lines. Human hybridoma technology (trioma technology) is also described by Vollmers et al. Histology and Histopathology 20(3):927-937 (2005) and Vollmers et al. Methods and Findings in Experimental and Clinical Pharmacology 27(3):185-91 (2005). Human antibodies can also be generated by isolating Fv clone variable domain sequences selected from human-derived phage display libraries. Such variable domain sequences may then be combined with the desired human constant domain. Techniques for selecting human antibodies from antibody libraries are described below.

In some embodiments of any of the antibodies provided herein, the antibody is a human antibody isolated by in vitro methods and/or screening combinatorial libraries for antibodies with the desired activity(s) is. Suitable examples include, but are not limited to, phage display (CAT, Morphosys, Dyax, Biosite/Medarex, Xoma, Symphogen, Alexion (formerly Proliferon), Affimed), ribosome display (CAT), yeast display (Adimab), etc. not. In one particular phage display method, repertoires of VH and VL genes are separately cloned by polymerase chain reaction (PCR) and randomly recombined in a phage library, which are subsequently described in Winter et al. Ann. Rev. Immunol. 12:433-455 (1994). For example, various methods are known in the art for generating phage display libraries and screening such libraries for antibodies with desired binding properties. Sidhu et al. J. Mol. Biol. 338(2):299-310, 2004, Lee et al. J. Mol. Biol. 340(5):1073-1093, 2004, Fellowe Proc. Natl. Acad. Sci. USA 101(34):12467-12472 (2004), and Lee et al. J. Immunol. See also Methods 284(-2):1 19-132 (2004). Phage typically display antibody fragments either as single-chain Fv (scFv) fragments or as Fab fragments. Libraries from immunization sources provide high-affinity antibodies to immunogens without the need for hybridoma construction. Alternatively, Griffiths et al. , EMBO J, 12:725-734 (1993), by cloning a naive repertoire (eg, from humans) to generate single antibodies against a wide range of non-self and self-antigens without any immunization. A single source can be provided. Finally, the naive library is also described by Hoogenboom et al. J. Mol. Biol. , 227:381-388, 1992, unrearranged V gene segments from stem cells were cloned, using PCR primers containing random sequences to encode the hypervariable HVR3 region, and regenerated in vitro. It can be made synthetically by achieving a sequence. Patent publications describing human antibody phage libraries include, for example, US Pat. Antibodies isolated from human antibody libraries are considered human antibodies or human antibody fragments herein.

(5) Constant Region Comprising Fc Region In some embodiments of any of the antibodies provided herein, the antibody comprises an Fc. In some embodiments, the Fc is of human IgG1, IgG2, IgG3, and/or IgG4 isotypes. In some embodiments, the antibody is of the IgG, IgM, or IgA class.

In certain embodiments of any of the antibodies provided herein, the antibody has the IgG2 isotype. In some embodiments, the antibody comprises a human IgG2 constant region. In some embodiments, the human IgG2 constant region comprises an Fc region. In some embodiments, the antibody induces one or more MerTK activities independent of binding to an Fc receptor. In some embodiments, the antibody binds to an inhibitory Fc receptor. In certain embodiments, said inhibitory Fc receptor is inhibitory Fc-gamma receptor IIB (FcγIIB).

In certain embodiments of any of the antibodies provided herein, the antibody has the IgG1 isotype. In some embodiments, the antibody comprises a murine IgG1 constant region. In some embodiments, the antibody comprises a human IgG1 constant region. In some embodiments, the human IgG1 constant region comprises an Fc region. In some embodiments, the antibody binds to an inhibitory Fc receptor. In certain embodiments, said inhibitory Fc receptor is inhibitory Fc-gamma receptor IIB (FcγIIB).

In certain embodiments of any of the antibodies provided herein, the antibody has the IgG4 isotype. In some embodiments, the antibody comprises a human IgG4 constant region. In some embodiments, the human IgG4 constant region comprises an Fc region. In some embodiments, the antibody binds to an inhibitory Fc receptor. In certain embodiments, said inhibitory Fc receptor is inhibitory Fc-gamma receptor IIB (FcγIIB).

In certain embodiments of any of the antibodies provided herein, the antibody has a hybrid IgG2/4 isotype. In some embodiments, the antibody comprises an amino acid sequence comprising amino acids 118-260 according to the EU numbering of human IgG2 and amino acids 261-447 according to the EU numbering of human IgG4 (WO1997/11971, WO2007/106585).

In some embodiments, said Fc region has increased clustering without activating complement compared to a corresponding antibody comprising an Fc region without said amino acid substitution. In some embodiments, the antibody induces one or more activities of the target to which it specifically binds. In some embodiments, the antibody binds to MerTK.

It may also be desirable to modify the anti-MerTK antibodies of this disclosure to alter effector function and/or increase the serum half-life of the antibodies. For example, by altering or mutating the binding site of the constant region of said Fc receptor to remove or reduce binding affinity for certain Fc receptors, e.g., FcγRI, FcγRII and/or FcγRIII, antibody dependent cells may reduce cytotoxicity mediated by In some embodiments, the effector function is reduced by removing N-glycosylation of the Fc region of the antibody (eg, in the CH2 domain of IgG). In some embodiments, the effector function is as described in WO99/58572 and Armor et al. , Molecular Immunology 40:585-593 (2003), Reddy et al. , J. Immunology 164:1925-1933 (2000), it is reduced by modifying regions such as 233-236, 297, and/or 327-331 of human IgG. In other embodiments, the anti-MerTK antibodies of the present disclosure are engineered to alter effector function, enhance detection selectivity to ITIM-containing FcgRIIb (CD32b), and enhance antibody-dependent cell-mediated cytotoxicity and antibody-dependent cell-mediated cytotoxicity. It may also be desirable to increase the clustering of MerTK antibodies in neighboring cells without activating humoral responses, including phagocytosis of the cells.

Salvage receptor binding epitopes, eg, as described in US Pat. No. 5,739,277, may be incorporated into antibodies (particularly antibody fragments) to increase the serum half-life of the antibodies. As used herein, the term "salvage receptor binding epitope" refers to an epitope of the Fc region of an IgG molecule (e.g., _IgG1 , _IgG2 , _IgG3 , or _IgG4 ), and the in vivo serum of the IgG molecule. Involved in half-life prolongation. Other amino acid sequence modifications.

(6) Antibody Variants In some embodiments of any of the antibodies provided herein, amino acid sequence variants of the antibody are contemplated. For example, it may be desirable to improve the binding affinity and/or other biological properties of the antibody.

(i) Substitution, Insertion, and Deletion Variants In some embodiments of any of the antibodies provided herein, antibody variants with one or more amino acid substitutions are provided. Amino acid sequence variants of an antibody may be prepared by introducing appropriate modifications into the nucleotide sequence encoding the antibody, or by peptide synthesis. Such modifications include, for example, deletions from and/or insertions into and/or substitutions of residues within the amino acid sequence of the antibody.

Substantial modification of an antibody's biological properties is achieved by selecting substitutions that are: (a) the structure of the polypeptide backbone, e.g., a sheet or helical structure, in the substitution region; The charge or hydrophobicity of the molecule or (c) their effect on maintaining the bulk of the side chains differ significantly. Naturally occurring residues are classified based on the following general side chain properties:
(1) Hydrophobic: Norleucine, Met, Ala, Val, Leu, Ile,
(2) Neutral hydrophilicity: Cys, Ser, Thr, Asn, Gln,
(3) acidic: Asp, Glu,
(4) basic: His, Lys, Arg,
(5) residues that influence chain orientation: Gly, Pro; and (6) aromatics: Trp, Tyr, Phe.

For example, non-conservative substitutions may involve exchanging a member of one of these classes for a member of another class. Such substituted residues may be introduced, for example, into regions of a human antibody that are homologous with non-human antibodies, or into the non-homologous regions of the molecule.

In making modifications to the polypeptides or antibodies described herein, according to certain embodiments, the hydropathic index of amino acids may be considered. Each amino acid has been assigned a hydropathic index based on its hydrophobicity and charge characteristics. They are: isoleucine (+4.5), valine (+4.2), leucine (+3.8), phenylalanine (+2.8), cysteine/cystine (+2.5), methionine (+1.9). ), alanine (+1.8), glycine (-0.4), threonine (-0.7), serine (-0.8), tryptophan (-0.9), tyrosine (-1.3), proline (-1.6), histidine (-3.2), glutamic acid (-3.5), glutamine (-3.5), aspartic acid (-3.5), asparagine (-3.5), lysine (-3.5) -3.9), and arginine (-4.5).

The importance of the hydropathic index of amino acids in conferring interactive biological function on proteins is understood in the art. Kyte et al. J. Mol. Biol. , 157:105-131 (1982). It is known that certain amino acids can be substituted with other amino acids having a similar hydropathic index or score and still retain similar biological activity. In making changes based on hydropathic index, certain embodiments include substitution of amino acids whose hydropathic index is within ±2. In certain embodiments, within ±1 is included, and in certain embodiments within ±0.5.

As in this case, substitution of like amino acids is preferred on the basis of hydrophilicity, especially when the biologically functional protein or peptide to be created is intended for use in immunological embodiments. It is also understood in the art that this can be effectively done. In certain embodiments, the maximum local average hydrophilicity of a protein, controlled by the hydrophilicity of adjacent amino acids, correlates with its immunogenicity and antigenicity, ie, the biological properties of the protein.

These amino acid residues have been assigned the following hydrophilicity values: arginine (+3.0), lysine (+3.0±1), aspartic acid (+3.0±1), glutamic acid (+3.0). ±1), serine (+0.3), asparagine (+0.2), glutamine (+0.2), glycine (0), threonine (-0.4), proline (-0.5±1), alanine ( -0.5), histidine (-0.5), cysteine (-1.0), methionine (-1.3), valine (-1.5), leucine (-1.8), isoleucine (-1 .8), tyrosine (-2.3), phenylalanine (-2.5) and tryptophan (-3.4). In making changes based on similar hydrophilicity values, certain embodiments include substitution of amino acids whose hydrophilicity values are within ±2, and in certain embodiments those within ±1. included, and in certain embodiments included within ±0.5. Epitopes can also be identified from primary amino acid sequences on the basis of hydrophilicity. These regions are also called "epitopic core regions".

In certain embodiments of the above variant VH and VL sequences, each HVR is unchanged.

Amino acid sequence insertions include amino- and/or carboxyl-terminal fusions ranging in length from one residue to polypeptides containing a hundred or more residues, as well as sequences of single or multiple amino acid residues. Intrasequence insertions are included. Examples of terminal insertions include antibodies with N-terminal methionyl residues. Other insertional variants of the antibody molecule include fusions of the antibody's N-terminus or C-terminus to enzymes (eg, for ADEPT) or to polypeptides that increase the serum half-life of the antibody.

Any cysteine residues that are outside the HVR and not involved in maintaining the proper conformation of the antibody are also commonly replaced with serines, which may improve the oxidative stability of the molecule and prevent aberrant cross-linking. be. Conversely, cysteine bond(s) may be added to the antibody to improve antibody stability (especially when the antibody is an antibody fragment such as an Fv fragment).

(ii) Glycosylation Variants In some embodiments of any of the antibodies provided herein, the antibody is modified to increase or decrease the degree to which the antibody is glycosylated. Addition or deletion of glycosylation sites to the antibody may conveniently be accomplished by altering the amino acid sequence such that one or more glycosylation sites are created or removed.

Glycosylation of antibodies is typically either N-linked or O-linked. N-linked refers to the attachment of carbohydrate moieties to the side chains of asparagine residues. The tripeptide sequences asparagine-X-serine and asparagine-X-threonine (where X is any amino acid except proline) are recognition sequences for enzymatic attachment of the carbohydrate moiety to the asparagine side chain. Thus, the presence of either of these tripeptide sequences within a polypeptide creates a potential glycosylation site. O-linked glycosylation refers to the attachment of one of the sugars N-acetylgalactosamine, galactose, or xylose to a hydroxyamino acid, most commonly serine or threonine, although 5-hydroxyproline or 5-hydroxylysine can also be used.

Addition of glycosylation sites to the antibody is conveniently accomplished by altering the amino acid sequence such that it contains one or more of the above tripeptide sequences (N-linked glycosylation sites for). The alterations may also be made by adding or substituting one or more serine or threonine residues to the original antibody sequence (for O-linked glycosylation sites).

Where the antibody contains an Fc region, the carbohydrate attached thereto may be altered. Natural antibodies produced by mammalian cells usually contain branched or biantennary oligosaccharides, which are generally N-linked to Asn297 according to the Kabat numbering of the CH2 domain of the Fc region. The oligosaccharides can include various carbohydrates such as mannose, N-acetylglucosamine (GlcNAc), galactose, and sialic acid, as well as fucose attached to GlcNAc in the "stem" of the biantennary oligosaccharide structure. In some embodiments, oligosaccharide modifications in antibodies of this disclosure may be made to create antibody variants with improved certain properties.

In one embodiment, antibody variants are provided that have fucose-free carbohydrate structures attached (directly or indirectly) to the Fc region. See, for example, US Patent Publication Nos. 2003/0157108 and 2004/0093621. Examples of publications relating to "defucosylated" or "fucose deficient" antibody variants include US2003/0157108, US2003/0115614, US2002/0164328, US2004/0093621, US2004/0132140, US2004/0110704, US2004/0110282, US 2004/0109865, Okazaki et al. J. Mol. Biol. 336:1239-1249 (2004), Yamane-Ohnuki et al. Biotech. Bioeng. 87:614 (2004). Examples of cell lines capable of producing defucosylated antibodies include Led 3 CHO cells deficient in protein fucosylation (Ripka et al. Arch. Biochem. Biophys. 249:533-545 (1986), US2003/ 0157108), and knockout cell lines such as the alpha-1,6-fucosyltransferase gene, FUT8, knockout CHO cells (eg Yamane-Ohnuki et al. Biotech. Bioeng. 87:614 (2004) and Kanda et al. Biotechnol Bioeng.94(4):680-688 (2006)).

(iii) Modified Constant Regions In some embodiments of any of the antibodies provided herein, the Fc of the antibody is of the Fc isotype and/or variant of the antibody. In some embodiments, the Fc isotype and/or variant of said antibody is capable of binding to an Fc gamma receptor.

In some embodiments of any of the antibodies provided herein, the Fc of the modified antibody is an IgG1 modified Fc. In some embodiments, the IgG1 modified Fc comprises one or more modifications. For example, in some embodiments, the IgG1 modified Fc comprises one or more amino acid substitutions (eg, relative to a wild-type Fc region of the same isotype). In some embodiments, the one or more amino acid substitutions are N297A (Bolt S et al. (1993) Eur J Immunol 23:403-411), D265A (Shields et al. (2001) RJ Biol Chem. 276, 6591-6604), L234A, L235A (Hutchins et al. (1995) Proc Natl Acad Sci USA, 92:11980-11984, Alegre et al., (1994) Transplantation 57:1537-1543.3. Xu et al., (2000) Cell Immunol, 200:16-26), G237A (Alegre et al. (1994) Transplantation 57:1537-1543.31, Xu et al. (2000) Cell Immunol, 200:16- 26), C226S, C229S, E233P, L234V, L234F, L235E (McEarchern et al., (2007) Blood, 109:1185-1192), P331S (Sazinsky et al., (2008) Proc Natl Acad Sci 08 USA 150 : 20167-20172), S267E, L328F, A330L, M252Y, S254T, and/or T256E. The amino acid positions in this case follow the EU numbering rules.

In some embodiments of any of the IgG1 modified Fc, the Fc comprises the N297A mutation according to EU numbering. In some embodiments of any of the IgG1 modified Fc, the Fc comprises the D265A and N297A mutations according to EU numbering. In some embodiments of any of the IgG1 modified Fc, the Fc comprises the D270A mutation according to EU numbering. In some embodiments, the IgG1 modified Fc comprises the L234A and L235A mutations according to EU numbering. In some embodiments of any of the IgG1 modified Fc, the Fc comprises the L234A and G237A mutations according to EU numbering. In some embodiments of any of the IgG1 modified Fc, the Fc comprises the L234A, L235A and G237A mutations according to EU numbering. In some embodiments of any of the IgG1 modified Fc, the Fc has one or more (including all) mutations of P238D, L328E, E233, G237D, H268D, P271G and A330R according to EU numbering. include. In some embodiments of any of the IgG1 modified Fc, the Fc comprises one or more mutations of S267E/L328F according to EU numbering. In some embodiments of any of the IgG1 modified Fc, the Fc comprises the P238D, L328E, E233D, G237D, H268D, P271G and A330R mutations according to EU numbering. In some embodiments of any of the IgG1 modified Fc, the Fc comprises the P238D, L328E, G237D, H268D, P271G and A330R mutations according to EU numbering. In some embodiments of any of the IgG1 modified Fc, the Fc comprises the P238D, S267E, L328E, E233D, G237D, H268D, P271G and A330R mutations according to EU numbering. In some embodiments of any of the IgG1 modified Fc, the Fc comprises the P238D, S267E, L328E, G237D, H268D, P271G and A330R mutations according to EU numbering. In some embodiments of any of the IgG1 modified Fc, the Fc comprises the C226S, C229S, E233P, L234V, and L235A mutations according to EU numbering. In some embodiments of any of the IgG1 modified Fc, the Fc comprises the L234F, L235E, and P331S mutations according to EU numbering. In some embodiments of any of the IgG1 modified Fc, the Fc comprises the S267E and L328F mutations according to EU numbering. In some embodiments of any of the IgG1 modified Fc, the Fc comprises N325S and L328F mutations according to EU numbering. In some embodiments of any of the IgG1 modified Fc, the Fc comprises the S267E mutation according to EU numbering. In some embodiments of any of the IgG1 modified Fc, the Fc comprises the constant heavy chain 1 (CH1) of IgG1 and the hinge region of the CH1 and hinge region of IgG2 (amino acids 118-230 according to EU numbering of IgG2). ) with the kappa light chain.

In some embodiments of any of said IgG1 modified Fc, said Fc comprises two or more amino acid substitutions, said substitutions corresponding to an antibody having an Fc region that does not comprise said two or more amino acid substitutions increases clustering of antibodies without activating complement compared to Thus, in some embodiments of any of said IgG1 modified Fc, said IgG1 modified Fc is an antibody comprising an Fc region, said antibody having an amino acid substitution at position E430G according to EU numbering and L234F, L235A , L235E, S267E, K322A, L328F, A330S, P331S, and any combination thereof. In some embodiments, the IgG1 modified Fc comprises amino acid substitutions at positions E430G, L243A, L235A, and P331S according to EU numbering. In some embodiments, the IgG1 modified Fc comprises amino acid substitutions at positions E430G and P331S according to EU numbering. In some embodiments, the IgG1 modified Fc comprises amino acid substitutions at positions E430G and K322A according to EU numbering. In some embodiments, the IgG1 modified Fc comprises amino acid substitutions at positions E430G, A330S, and P331S according to EU numbering. In some embodiments, the IgG1 modified Fc comprises amino acid substitutions at positions E430G, K322A, A330S, and P331S according to EU numbering. In some embodiments, the IgG1 modified Fc comprises amino acid substitutions at positions E430G, K322A, and A330S according to EU numbering. In some embodiments, the IgG1 modified Fc comprises amino acid substitutions at positions E430G, K322A, and P331S according to EU numbering.

In some embodiments of any of said IgG1 modified Fc, said IgG1 modified Fc herein further comprises an A330L mutation according to EU numbering rules (Lazar et al. Proc Natl Acad Sci USA, 103:4005-4010 (2006)), or one or more mutations of L234F, L235E, and/or P331S (Sazinsky et al. Proc Natl Acad Sci USA, 105:20167-20172 ( 2008))). In some embodiments of any of the IgG1 modified Fc, the IgG1 modified Fc may further comprise one or more of A330L, A330S, L234F, L235E, and/or P331S according to EU numbering. In some embodiments of any of the IgG1 modified Fc, the IgG1 modified Fc further comprises one or more mutations to increase the half-life of the antibody in human serum (e.g., EU numbering one or more (including all) of M252Y, S254T, and T256E according to the rules). In some embodiments of any of the IgG1 modified Fc, the IgG1 modified Fc is further E430G, E430S, E430F, E430T, E345K, E345Q, E345R, E345Y, S440Y, and/or S440W according to EU numbering. may include one or more of

Another aspect of this disclosure pertains to antibodies with altered constant regions (ie, Fc regions). Antibodies that rely on binding to FcgR receptors to activate target receptors may lose agonist activity if engineered to eliminate FcgR binding (e.g., Wilson et al. Cancer Cell 19 : 101-113 (2011), Armor at al. Immunology 40:585-593 (2003), and White et al. Cancer Cell 27:138-148 (2015)). Thus, anti-MerTK antibodies of the present disclosure with correct epitope specificity preferentially bind to Fc domains derived from human IgG2 isotype (CH1 and hinge region) or inhibitory FcgRIIB r receptors or variants thereof. Having another type of Fc domain capable of activating the target antigen would be possible with minimal adverse effects.

In some embodiments of any of the antibodies provided herein, the Fc of the modified antibody is an IgG2 modified Fc. In some embodiments, the IgG2 modified Fc comprises one or more modifications. For example, in some embodiments, the IgG2 modified Fc comprises one or more amino acid substitutions (eg, relative to a wild-type Fc region of the same isotype). In some embodiments of any of said IgG2 modified Fc, said one or more amino acid substitutions are V234A according to EU numbering conventions (Alegre et al. Transplantation 57:1537-1543 (1994), Xu et al. Cell Immunol, 200:16-26 (2000), G237A (Cole et al. Transplantation, 68:563-571 (1999), H268Q, V309L, A330S, P331S (US2007/0148167, Armour et al. Eur J Immunol 29: 2613-2624 (1999), Armor et al.The Haematology Journal 1(Suppl.1):27(2000), Armor et al. or from C220S (White et al. Cancer Cell 27, 138-148 (2015)), S267E, L328F (Chu et al. Mol Immunol, 45:3926-3933 (2008)), and M252Y, S254T, and/or T256E In some embodiments of any of said IgG2 modified Fc, said Fc comprises amino acid substitutions at positions V234A and G237A according to EU numbering. In a form, said Fc comprises amino acid substitutions at positions C219S and C220S according to EU numbering, hi some embodiments of any of said IgG2 modified Fc, said Fc comprises amino acid substitutions at positions A330S and P331S according to EU numbering In some embodiments of any of said IgG2 modified Fc, said Fc comprises amino acid substitutions at positions S267E and L328F according to EU numbering.

In some embodiments of any of the IgG2 modified Fc, the Fc comprises a C127S amino acid substitution according to EU numbering rules (White et al., (2015) Cancer Cell 27, 138-148, Light et al. Protein Sci., 19:753-762 (2010), and WO2008/079246). In some embodiments of any of the IgG2 modified Fc, the antibody has an IgG2 isotype with a kappa light chain constant domain comprising a C214S amino acid substitution according to EU numbering rules (White et al. Cancer Cell 27: 138-148 (2015), Light et al. Protein Sci. 19:753-762 (2010), and WO2008/079246).

In some embodiments of any of the IgG2 modified Fc, the Fc comprises a C220S amino acid substitution according to EU numbering rules. In some embodiments of any of the IgG2 modified Fc, the antibody has an IgG2 isotype with a kappa light chain constant domain comprising a C214S amino acid substitution according to EU numbering rules.

In some embodiments of any of the IgG2 modified Fc, the Fc comprises a C219S amino acid substitution according to EU numbering rules. In some embodiments of any of the IgG2 modified Fc, the antibody has an IgG2 isotype with a kappa light chain constant domain comprising a C214S amino acid substitution according to EU numbering rules.

In some embodiments of any of the IgG2 modified Fc, the Fc comprises a heavy chain constant domain 1 (CH1) and hinge region of the IgG2 isotype (White et al. Cancer Cell 27:138-148 (2015). )). In certain embodiments of any of said IgG2 modified Fc's, the CH1 and hinge regions of said IgG2 isotype comprise the amino acid sequence 118-230 according to EU numbering. In some embodiments of any of the IgG2 modified Fc, the Fc region of the antibody has an S267E amino acid substitution, an L328F amino acid substitution, or both, and/or an N297A or N297Q amino acid substitution according to EU numbering rules including.

In some embodiments of any of said IgG2 modified Fc, said Fc is further at one or more of positions E430G, E430S, E430F, E430T, E345K, E345Q, E345R, E345Y, S440Y, and S440W according to EU numbering. containing amino acid substitutions of In some embodiments of any of said IgG2 modified Fc, said Fc further comprises one or more mutations to increase the half-life of said antibody in human serum (e.g., M252Y according to EU numbering rules). , S254T, and T256E mutations). In some embodiments of any of the IgG2 modified Fc, the Fc may further comprise A330S and P331S.

In some embodiments of any of the IgG2 modified Fc, the Fc is an IgG2/4 hybrid Fc. In some embodiments, the IgG2/4 hybrid Fc comprises aa118-260 of IgG2 and aa261-447 of IgG4. In some embodiments of any IgG2 modified Fc, said Fc comprises one or more amino acid substitutions at positions H268Q, V309L, A330S, and P331S according to EU numbering.

In some embodiments of any of the IgG1 and/or IgG2 modified Fc, the Fc is one or more selected from A330L, L234F, L235E, or P331S according to EU numbering, and any combination thereof. Including additional amino acid substitutions.

In certain embodiments of any of said IgG1 and/or IgG2 modified Fc, said Fc is C127S, L234A, L234F, L235A, L235E, S267E, K322A, L328F, A330S, P331S, E345R, E430G according to EU numbering , S440Y, and any combination thereof. In some embodiments of any of the IgG1 and/or IgG2 modified Fc, the Fc comprises amino acid substitutions at positions E430G, L243A, L235A, and P331S according to EU numbering. In some embodiments of any of the IgG1 and/or IgG2 modified Fc, the Fc comprises amino acid substitutions at positions E430G and P331S according to EU numbering. In some embodiments of any of the IgG1 and/or IgG2 modified Fc, the Fc comprises amino acid substitutions at positions E430G and K322A according to EU numbering. In some embodiments of any of the IgG1 and/or IgG2 modified Fc, the Fc comprises amino acid substitutions at positions E430G, A330S, and P331S according to EU numbering. In some embodiments of any of the IgG1 and/or IgG2 modified Fc, the Fc comprises amino acid substitutions at positions E430G, K322A, A330S, and P331S according to EU numbering. In some embodiments of any of the IgG1 and/or IgG2 modified Fc, the Fc comprises amino acid substitutions at positions E430G, K322A, and A330S according to EU numbering. In some embodiments of any of the IgG1 and/or IgG2 modified Fc, the Fc comprises amino acid substitutions at positions E430G, K322A, and P331S according to EU numbering. In some embodiments of any of the IgG1 and/or IgG2 modified Fc, the Fc comprises amino acid substitutions at positions S267E and L328F according to EU numbering. In some embodiments of any of the IgG1 and/or IgG2 modified Fc, the Fc comprises an amino acid substitution at position C127S according to EU numbering. In some embodiments of any of the IgG1 and/or IgG2 modified Fc, the Fc comprises amino acid substitutions at positions E345R, E430G and S440Y according to EU numbering.

In some embodiments of any of the antibodies provided herein, the Fc of the modified antibody is an IgG4 modified Fc. In some embodiments, the IgG4 modified Fc comprises one or more modifications. For example, in some embodiments, the IgG4 modified Fc comprises one or more amino acid substitutions (eg, relative to a wild-type Fc region of the same isotype). In some embodiments of any of the IgG4 modified Fc, the one or more amino acid substitutions are L235A, G237A, S229P, L236E according to EU numbering conventions (Reddy et al. J Immunol 164:1925-1933 (2000). )), S267E, E318A, L328F, M252Y, S254T, and/or T256E. In some embodiments of any of the IgG4 modified Fc, the Fc may further comprise L235A, G237A, and E318A according to EU numbering conventions. In some embodiments of any of the IgG4 modified Fc, the Fc may further comprise S228P and L235E according to EU numbering rules. In some embodiments of any of said IgG4 modified Fc, said IgG4 modified Fc may further comprise S267E and L328F according to EU numbering rules.

In some embodiments of any of the IgG4 modified Fc, the IgG4 modified Fc has an S228P mutation according to EU numbering rules (Angal et al. Mol Immunol. 30:105) to enhance antibody stability. -108 (1993)) and/or (Peters et al. J Biol Chem. 287(29):24525-33 (2012)).

In some embodiments of any of the IgG4 modified Fc, the IgG4 modified Fc further comprises one or more mutations to increase the half-life of the antibody in human serum (e.g., EU numbering one or more (including all) of M252Y, S254T, and T256E according to the rules).

In some embodiments of any of the IgG4 modified Fc, the Fc comprises L235E according to EU numbering. In certain embodiments of any of said IgG4 modified Fc, said Fc is from C127S, F234A, L235A, L235E, S267E, K322A, L328F, E345R, E430G, S440Y, and any combination thereof according to EU numbering Include one or more amino acid substitutions at selected residue positions. In some embodiments of any of the IgG4 modified Fc, the Fc comprises amino acid substitutions at positions E430G, L243A, L235A, and P331S according to EU numbering. In some embodiments of any of said IgG4 modified Fc, said Fc comprises amino acid substitutions at positions E430G and P331S according to EU numbering. In some embodiments of any of the IgG4 modified Fc, the Fc comprises amino acid substitutions at positions E430G and K322A according to EU numbering. In some embodiments of any of said IgG4 modified Fc, said Fc comprises an amino acid substitution at position E430 according to EU numbering. In some embodiments of any of the IgG4 modified Fc, the Fc region comprises amino acid substitutions at positions E430G and K322A according to EU numbering. In some embodiments of any of the IgG4 modified Fc, the Fc comprises amino acid substitutions at positions S267E and L328F according to EU numbering. In some embodiments of any of said IgG4 modified Fc, said Fc comprises an amino acid substitution at position C127S according to EU numbering. In some embodiments of any of said IgG4 modified Fc, said Fc comprises amino acid substitutions at positions E345R, E430G and S440Y according to EU numbering.

(7) Other Antibody Modifications In some embodiments of any of the antibodies, the antibody is a derivative. The term "derivative" refers to molecules containing chemical modifications other than amino acid (or nucleic acid) insertions, deletions, or substitutions. In certain embodiments, derivatives comprise covalent modifications including, but not limited to, chemical bonding with polymers, lipids, or other organic or inorganic moieties. In certain embodiments, a chemically modified antigen binding protein may have a longer blood half-life than a chemically unmodified antigen binding protein. In certain embodiments, chemically modified antigen binding proteins may have improved targeting capabilities to desired cells, tissues, and/or organs. In some embodiments, the derivative antigen binding protein is covalently modified to include one or more water soluble polymer connections, including but not limited to polyethylene glycol, polyoxyethylene glycol, or polypropylene glycol. be. See, for example, U.S. Pat. In certain embodiments, the derivative antigen binding protein is monomethoxy-polyethylene glycol, dextran, cellulose, ethylene glycol/propylene glycol copolymer, carboxymethylcellulose, polyvinylpyrrolidone, poly-1,3-dioxolane, poly-1, 3,6-trioxane, ethylene/maleic anhydride copolymer, polyamino acid (either homopolymer or random copolymer), poly(N-vinylpyrrolidone)-polyethylene glycol, propylene glycol homopolymer, polypropylene oxide/ethylene oxide copolymer, polyoxy One or more polymers including, but not limited to, ethylated polyols (eg, glycerol), and polyvinyl alcohol, and mixtures of such polymers.

In certain embodiments, derivatives are covalently modified with polyethylene glycol (PEG) subunits. In certain embodiments, one or more water-soluble polymers are attached at one or more specific positions of the derivative, eg, the amino terminus. In certain embodiments, one or more water-soluble polymers are randomly attached to one or more side chains of the derivative. In certain embodiments, PEG is used to improve the therapeutic potency of antigen binding proteins. In certain embodiments, PEG is used to improve the therapeutic potential of humanized antibodies. Certain such methods are discussed, for example, in US Pat. No. 6,133,426, which is incorporated herein by reference for any purpose.

Peptide analogs are commonly used in the pharmaceutical industry as non-peptide drugs with properties similar to those of the template peptide. These types of non-peptide compounds are called "peptidomimetics" or "peptidomimetics." Fauchere, J.; Adv. Drug Res. , 15:29 (1986), and Evans et al. J. Med. Chem. , 30:1229 (1987), which are incorporated herein by reference for any purpose. Such compounds are often developed using computerized molecular modeling. Peptide mimetics that are structurally similar to therapeutically useful peptides can be used to produce similar therapeutic effects. In general, peptidomimetics are structurally similar to paradigm polypeptides (i.e., polypeptides with biochemical properties or pharmacological activity), e.g., human antibodies, but by methods well known in the art- CH ₂ NH-, -CH ₂ S-, -CH ₂ -CH ₂ -, -CH=CH- (cis and trans), -COCH ₂ -, -CH(OH)CH ₂ -, and -CH ₂ SO- has one or more peptide bonds optionally substituted with a bond selected from In certain embodiments, systematic substitution of one or more amino acids of a consensus sequence with a D-amino acid of the same type (eg, D-lysine in place of L-lysine) is used to generate more stable peptides. can be generated. In addition, conformationally constrained peptides comprising a consensus sequence or variations of a substantially identical consensus sequence can be produced using methods known in the art (Rizo and Gierasch Ann. Rev. Biochem., 61:387 (1992). ), incorporated herein by reference for any purpose), for example by adding an internal cysteine residue capable of forming an intramolecular disulfide bridge that cyclizes the peptide. .

Drug conjugation provides antibodies that specifically target certain tumor markers (e.g., ideally polypeptides found only in or on tumor cells) with bioactive cytotoxic (anti-tumor) n) including coupling payloads or drugs. Antibodies find these proteins in the body and bind to the surface of cancer cells. A biochemical reaction between the antibody and the target protein (antigen) triggers a signal within the tumor cells, which then take up or internalize the antibody along with the cytotoxin. After the ADC is internalized, the cytotoxic drug is released and kills the cancer. Because of this targeting, the drug ideally has fewer side effects and a broader therapeutic window than other chemotherapeutic agents. Techniques for conjugating antibodies have been disclosed and are known in the art (see, for example, Jane de Lartigue OncLive July 5, 2012, ADC Review on antibody-drug conjugates, and Ducry et al. Bioconjugate Chemistry 21 (1 ): 5-13 (2010)).

II. Nucleic Acids, Vectors, and Host Cells Anti-MerTK antibodies of the present disclosure can be produced using recombinant methods and compositions described, for example, in US Pat. No. 4,816,567. In some embodiments, an isolated nucleic acid having a nucleotide sequence encoding any of the anti-MerTK antibodies of this disclosure is provided. Such nucleic acids can encode amino acid sequences comprising the V _L and/or V _H of the anti-MerTK antibody (eg, the light and/or heavy chains of the antibody). In some embodiments, one or more vectors (eg, expression vectors) are provided that contain such nucleic acids. In some embodiments, host cells comprising such nucleic acids are also provided. In some embodiments, the host cell comprises (1) a vector comprising a nucleic acid encoding an amino acid sequence comprising the V _L of the antibody and an amino acid sequence comprising the V _H of the antibody; or (2) the V comprising (eg, transformed with) a first vector comprising nucleic acid encoding an amino acid sequence comprising _L and a second vector comprising nucleic acid encoding an amino acid sequence comprising _VH of the antibody. In some embodiments, the host cells are eukaryotic, eg, Chinese Hamster Ovary (CHO) cells or lymphoid cells (eg, Y0, NS0, Sp20 cells). Host cells of the present disclosure also include, but are not limited to, isolated cells, in vitro cultured cells, and ex vivo cultured cells.

Methods of making anti-MerTK antibodies of the disclosure are provided. In some embodiments, the method comprises culturing a host cell of this disclosure comprising nucleic acid encoding the anti-MerTK antibody under conditions suitable for expression of the antibody. In some embodiments, the antibody is then recovered from the host cell (or host cell culture medium).

To recombinantly produce an anti-MerTK antibody of the disclosure, the nucleic acid encoding the anti-MerTK antibody is isolated and inserted into one or more vectors for further cloning and/or expression in host cells. Such nucleic acids are readily isolated using conventional procedures (e.g., by using oligonucleotide probes capable of specifically binding to the genes encoding the heavy and light chains of the antibody), can be sequenced.

Suitable vectors containing a nucleic acid sequence encoding any of the anti-MerTK antibodies of the disclosure, or a polypeptide (including antibodies) of a cell surface expressed fragment or polypeptide thereof described herein include cloning Examples include, but are not limited to, vectors and expression vectors. Suitable cloning vectors may be constructed according to standard methods or may be selected from a large number of cloning vectors available in the art. The cloning vector chosen may vary depending on the host cell intended for use, but useful cloning vectors are generally capable of self-replicating and may have a single target for a particular restriction endonuclease; and/or may have a marker gene that can be used to select clones containing the vector. Suitable examples include plasmids and bacterial viruses such as pUC18, pUC19, Bluescript (e.g. pBS SK+) and derivatives thereof, mpl8, mpl9, pBR322, pMB9, ColE1, pCR1, RP4, phage DNA, and shuttle vectors; Examples include pSA3 and pAT28. These and many other cloning vectors are available from commercial vendors such as BioRad, Strategene, and Invitrogen.

Suitable host cells for cloning or expression of antibody-encoding vectors include prokaryotic or eukaryotic cells. For example, anti-MerTK antibodies of the disclosure can be produced in bacteria, particularly when glycosylation and Fc effector function are not required. For expression of antibody fragments and polypeptides in bacteria (eg, US Pat. Nos. 5,648,237, 5,789,199, and 5,840,523). After expression, the antibody can be isolated from the soluble fraction of the bacterial cell paste and further purified.

In addition to prokaryotes, eukaryotic microbes such as filamentous fungi or yeast are also suitable cloning or expression hosts for antibody-encoding vectors, which have been "humanized" in their glycosylation pathways. , fungal and yeast strains that result in the production of antibodies with partially or completely human glycosylation patterns (eg, Gerngross, Nat. Biotech. 22:1409-1414 (2004), and Li et al. Nat. Biotech.24:210-215 (2006)).

Suitable host cells for the expression of glycosylated antibodies can also be obtained from multicellular organisms (invertebrates and vertebrates). Examples of invertebrate cells include plant cells and insect cells. A number of baculovirus strains have been identified that can be used for transfection of insect cells, as well as Spodoptera frugiperda cells in particular. Plant cell cultures can also be used as hosts (e.g., US Pat. Nos. 5,959,177, 6,040,498, 6,420,548, 7,125,978 and 6,417,429, PLANTIBODIES for the production of antibodies in transgenic plants). (trademark) technology).

Vertebrate cells can also be used as hosts. For example, mammalian cell lines adapted to grow in suspension may be useful. Other examples of useful host mammalian cell lines are the SV40-transformed monkey kidney CV1 strain (COS-7), the human embryonic kidney strain (293 cells, or see, for example, Graham et al., J. Gen Virol 293 cells as described in .36:59 (1977)), baby hamster kidney cells (BHK), mouse Sertoli cells (e.g. TM4 cells as described in Mather, Biol. Reprod. 23:243-251 (1980)), monkeys. Kidney cells (CV1), African green monkey kidney cells (VERO-76), human cervical cancer cells (HELA), canine kidney cells (MDCK, buffalo rat hepatocytes (BRL 3A), human lung cells (W138), human liver cells (Hep G2), mouse mammary tumors (MMT 060562) such as TRI cells, MRC5 cells, and FS4 cells as described in Mather et al., Annals NY Acad. Other useful mammalian host cell lines include Chinese Hamster Ovary (CHO) cells, including DHFR-CHO cells (Urlaub et al. Proc. Natl. Acad. Sci. USA 77:4216 (1980)). , and myeloma cell lines such as Y0, NS0 and Sp2/0, etc. For a review of certain mammalian host cell lines suitable for antibody production, see, eg, Yazaki and Wu, Methods in Molecular Biology, Vol. 248 (BKC Lo, ed., Humana Press, Totowa, NJ), pp. 255-268 (2003).

III. Pharmaceutical Compositions/Formulations Provided herein are pharmaceutical compositions and/or formulations comprising an anti-MerTK antibody of the disclosure and a pharmaceutically acceptable carrier.

In some embodiments, pharmaceutically acceptable carriers are preferably nontoxic to recipients at the dosages and concentrations employed. Pharmaceutical compositions and/or pharmaceutical formulations to be used for in vivo administration can be sterile. This is readily accomplished, for example, by filtration through sterile filtration membranes.

Pharmaceutical compositions and/or pharmaceutical formulations provided herein are useful, for example, as agents for the treatment of cancer.

IV. Therapeutic Uses As disclosed herein, the anti-MerTK antibodies of the disclosure can be used to treat diseases and disorders. In some embodiments, the disclosure provides a method of treating an individual with cancer, comprising administering to the individual a therapeutically effective amount of an anti-MerTK antibody of the disclosure.

Ectopic or expression of MerTK has been observed in various tumors, and overexpression and activation of MerTK has been implicated in lymphocytic leukemia, lymphoma, adenoma, melanoma, gastric cancer, prostate cancer, and breast cancer. , MerTK overexpression is associated with metastasis. (Schlegel et al, 2013, J Clin Invest, 123:2257-2267, Tworkoski et al, 2013, Pigment Cell Melanoma, 26:527-541, Yi et al, 2017, Oncotarget, 8:96656-96667, Linger et al. , 2013, Blood, 122:1599-1609, Lee-Sherick et al, 2013, Oncogene, 32:5359-5368, Brandao et al, 2013, Blood Cancer, 3: e101, Xie et al, 2015, Oncotarget, 6: 9206-9219, Shi et al, 2018, J Hematology & Oncology, 11:43). Therefore, modulating MerTK activity with the anti-MerTK antibodies of the present disclosure is an effective means of treating cancer.

In certain aspects, provided herein is a method of treating cancer in a subject in need thereof, wherein the method comprises treating the subject with an anti-MerTK antibody of the present disclosure, or administering a pharmaceutical composition comprising the disclosed anti-MerTK antibody. In some embodiments, a method of treating cancer in a subject in need thereof is provided, the method comprising administering to the subject an anti-MerTK antibody of the present disclosure, wherein the anti-MerTK Antibodies reduce efferocytosis by phagocytic cells. In some embodiments, a method of treating cancer in a subject in need thereof is provided, the method comprising administering to the subject an anti-MerTK antibody of the present disclosure, wherein the anti-MerTK Antibodies induce M1-like macrophage polarization.

In some embodiments, the cancer is sarcoma, bladder cancer, breast cancer, colon cancer, endometrial cancer, kidney cancer, renal cancer, leukemia, lung cancer, non-small cell lung cancer, melanoma, lymphoma, pancreatic cancer, prostate cancer, ovarian cancer, gastric cancer, thyroid cancer, uterine cancer, liver cancer, cervical cancer, testicular cancer, squamous cell carcinoma, glioma, glioblastoma, adenoma, and neuroblastoma Selected from cell tumors. In some embodiments, the cancer is selected from glioblastoma multiforme, bladder cancer, and esophageal cancer. In some embodiments, the cancer is triple negative breast cancer. In some embodiments, the cancer can be a primary tumor. In some embodiments, the cancer may be a secondary site metastatic tumor from any of the above cancer types. In some embodiments, the anti-MerTK antibodies of the present disclosure are useful for treating a MerTK-expressing cancer in a subject in need thereof.

In some embodiments, the anti-MerTK antibodies of this disclosure can be administered in combination with one or more therapeutic agents that act as checkpoint inhibitors. In some embodiments, the method further comprises administering to the individual at least one antibody that specifically binds to an inhibitory immune checkpoint molecule and/or another standard or investigational antibody. Including administering cancer treatment. In some embodiments, the inhibitory checkpoint molecule is selected from PD1, PD-L1, and PD-L2. In some embodiments, at least one antibody that specifically binds to the inhibitory checkpoint molecule is administered in combination with an anti-MerTK antibody of the disclosure.

In some embodiments, the at least one antibody that specifically binds to the inhibitory checkpoint molecule is selected from anti-PD-L1 antibodies, anti-PD-L2 antibodies, and anti-PD-1 antibodies.

In some embodiments, the subject or individual is a mammal. Mammals include farm animals (e.g., cows, sheep, cats, dogs, and horses), primates (e.g., humans and non-human primates such as monkeys), rabbits, and rodents (e.g., mice and rats). ), but are not limited to these. In some embodiments, the subject or individual is human.

V. Diagnostic Uses In some embodiments of any of the antibodies, any of the anti-MerTK antibodies provided herein are useful for detecting the presence of MerTK in a sample or in an individual. As used herein, the term "detection" encompasses quantitative or qualitative detection. Provided herein are methods of using the antibodies of the disclosure for diagnostic purposes, eg, for the detection of MerTK in an individual or in a tissue sample obtained from an individual. In some embodiments, the individual is human. In some embodiments, the tissue sample is phagocytic cells (eg, macrophages, dendritic cells), tumor tissue, cancer cells, and the like.

The detection method may involve quantification of antibody bound to the antigen. Antibody detection in biological samples is by any method known in the art, including immunofluorescence microscopy, immunocytochemistry, immunohistochemistry, ELISA, FACS analysis, immunoprecipitation, or micropositron emission tomography. can be done. In certain embodiments, the antibody is radiolabeled, eg, with ¹⁸ F, and then detected using micropositron emission tomography analysis. Antibody conjugation is also used in non-invasive techniques such as positron emission tomography (PET), X-ray computed tomography, single photon emission computed tomography (SPECT), computed tomography (CT), and computed axial tomography (CAT). can be quantified in patients by sexual techniques.

VI. Articles of Manufacture Provided herein are articles of manufacture (eg, kits) that include the anti-MerTK antibodies described herein. An article of manufacture may comprise one or more containers containing the antibodies described herein. The container can be any suitable packaging, including but not limited to vials, bottles, jars, flexible packaging (eg, sealed mylar or plastic bags), and the like. The containers may be unit doses, bulk packages (eg, multi-dose packages), or divided unit doses.

In some embodiments, the kit can further include a second agent. In some embodiments, the second agent is a pharmaceutically acceptable buffer or diluent. In some embodiments, the second agent is a pharmaceutically active agent.

In some embodiments of any of the articles of manufacture, the article of manufacture further comprises instructions for use according to the methods of the present disclosure. The instructions generally include information regarding dosages, dosing schedules and routes of administration for the intended treatment. In some embodiments, these instructions are isolated antibodies of the present disclosure (e.g., including instructions for administering anti-MerTK antibodies) according to any method of the present disclosure. In some embodiments, the instructions include instructions for using the anti-MerTK antibody and the second agent (eg, second pharmaceutically active agent).

The present disclosure will be more fully understood by reference to the following examples. They should not, however, be construed as limiting the scope of this disclosure. All references cited throughout this disclosure are expressly incorporated herein by reference.

Example 1 Production of His-Conjugated and Mouse Fc-Conjugated MerTK Polypeptides Including Poly-His or TEVS/Thrombin/Mouse IgG2a-Fc Tagged Fusion Proteins for Use in Generation and Characterization of Anti-MerTK Antibodies of the Disclosure , human, cynomolgus monkey, and mouse MerTK polypeptides were generated as follows. Nucleic acids encoding the extracellular domains (ECDs) of human MerTK (SEQ ID NO: 2), cynomolgus monkey MerTK (SEQ ID NO: 3), and mouse MerTK (SEQ ID NO: 4) were combined with nucleic acids encoding heterologous signal peptides and poly-His Cloned into mammalian expression vectors containing either Fc-tag or TEVS/thrombin/mouse IgG2a Fc-tag.

The amino acid sequences of human MerTK, human MerTK extracellular domain, cynomolgus monkey MerTK extracellular domain, and mouse MerTK extracellular domain are shown below.

Human MerTK amino acid sequence (SEQ ID NO: 1):
ＭＧＰＡＰＬＰＬＬＬＧＬＦＬＰＡＬＷＲＲＡＩＴＥＡＲＥＥＡＫＰＹＰＬＦＰＧＰＦＰＧＳＬＱＴＤＨＴＰＬＬＳＬＰＨＡＳＧＹＱＰＡＬＭＦＳＰＴＱＰＧＲＰＨＴＧＮＶＡＩＰＱＶＴＳＶＥＳＫＰＬＰＰＬＡＦＫＨＴＶＧＨＩＩＬＳＥＨＫＧＶＫＦＮＣＳＩＳＶＰＮＩＹＱＤＴＴＩＳＷＷＫＤＧＫＥＬＬＧＡＨＨＡＩＴＱＦＹＰＤＤＥＶＴＡＩＩＡＳＦＳＩＴＳＶＱＲＳＤＮＧＳＹＩＣＫＭＫＩＮＮＥＥＩＶＳＤＰＩＹＩＥＶＱＧＬＰＨＦＴＫＱＰＥＳＭＮＶＴＲＮＴＡＦＮＬＴＣＱＡＶＧＰＰＥＰＶＮＩＦＷＶＱＮＳＳＲＶＮＥＱＰＥＫＳＰＳＶＬＴＶＰＧＬＴＥＭＡＶＦＳＣＥＡＨＮＤＫＧＬＴＶＳＫＧＶＱＩＮＩＫＡＩＰＳＰＰＴＥＶＳＩＲＮＳＴＡＨＳＩＬＩＳＷＶＰＧＦＤＧＹＳＰＦＲＮＣＳＩＱＶＫＥＡＤＰＬＳＮＧＳＶＭＩＦＮＴＳＡＬＰＨＬＹＱＩＫＱＬＱＡＬＡＮＹＳＩＧＶＳＣＭＮＥＩＧＷＳＡＶＳＰＷＩＬＡＳＴＴＥＧＡＰＳＶＡＰＬＮＶＴＶＦＬＮＥＳＳＤＮＶＤＩＲＷＭＫＰＰＴＫＱＱＤＧＥＬＶＧＹＲＩＳＨＶＷＱＳＡＧＩＳＫＥＬＬＥＥＶＧＱＮＧＳＲＡＲＩＳＶＱＶＨＮＡＴＣＴＶＲＩＡＡＶＴＲＧＧＶＧＰＦＳＤＰＶＫＩＦＩＰＡＨＧＷＶＤＹＡＰＳＳＴＰＡＰＧＮＡＤＰＶＬＩＩＦＧＣＦＣＧＦＩＬＩＧＬＩＬＹＩＳＬＡＩＲＫＲＶＱＥＴＫＦＧＮＡＦＴＥＥＤＳＥＬＶＶＮＹＩＡＫＫＳＦＣＲＲＡＩＥＬＴＬＨＳＬＧＶＳＥＥＬＱＮＫＬＥＤＶＶＩＤＲＮＬＬＩＬＧＫＩＬＧＥＧＥＦＧＳＶＭＥＧＮＬＫＱＥＤＧＴＳＬＫＶＡＶＫＴＭＫＬＤＮＳＳＱＲＥＩＥＥＦＬＳＥＡＡＣＭＫＤＦＳＨＰＮＶＩＲＬＬＧＶＣＩＥＭＳＳＱＧＩＰＫＰＭＶＩＬＰＦＭＫＹＧＤＬＨＴＹＬＬＹＳＲＬＥＴＧＰＫＨＩＰＬＱＴＬＬＫＦＭＶＤＩＡＬＧＭＥＹＬＳＮＲＮＦＬＨＲＤＬＡＡＲＮＣＭＬＲＤＤＭＴＶＣＶＡＤＦＧＬＳＫＫＩＹＳＧＤＹＹＲＱＧＲＩＡＫＭＰＶＫＷＩＡＩＥＳＬＡＤＲＶＹＴＳＫＳＤＶＷＡＦＧＶＴＭＷＥＩＡＴＲＧＭＴＰＹＰＧＶＱＮＨＥＭＹＤＹＬＬＨＧＨＲＬＫＱＰＥＤＣＬＤＥＬＹＥＩＭＹＳＣＷＲＴＤＰＬＤＲＰＴＦＳＶＬＲＬＱＬＥＫＬＬＥＳＬＰＤＶＲＮＱＡＤＶＩＹＶＮＴＱＬＬＥＳＳＥＧＬＡＱＧＳＴＬＡＰＬＤＬＮＩＤＰＤＳＩＩＡＳＣＴＰＲＡＡＩＳＶＶＴＡＥＶＨＤＳＫＰＨＥＧＲＹＩＬＮＧＧＳＥＥＷＥＤＬＴＳＡＰＳＡＡＶＴＡＥＫＮＳＶＬＰＧＥＲＬＶＲＮＧＶＳＷＳＨＳＳＭＬＰＬＧＳＳＬＰＤＥＬＬＦＡＤＤＳＳＥＧＳＥＶＬＭ

Human MerTK ECD amino acid sequence (SEQ ID NO:2):
ＭＧＰＡＰＬＰＬＬＬＧＬＦＬＰＡＬＷＲＲＡＩＴＥＡＲＥＥＡＫＰＹＰＬＦＰＧＰＦＰＧＳＬＱＴＤＨＴＰＬＬＳＬＰＨＡＳＧＹＱＰＡＬＭＦＳＰＴＱＰＧＲＰＨＴＧＮＶＡＩＰＱＶＴＳＶＥＳＫＰＬＰＰＬＡＦＫＨＴＶＧＨＩＩＬＳＥＨＫＧＶＫＦＮＣＳＩＳＶＰＮＩＹＱＤＴＴＩＳＷＷＫＤＧＫＥＬＬＧＡＨＨＡＩＴＱＦＹＰＤＤＥＶＴＡＩＩＡＳＦＳＩＴＳＶＱＲＳＤＮＧＳＹＩＣＫＭＫＩＮＮＥＥＩＶＳＤＰＩＹＩＥＶＱＧＬＰＨＦＴＫＱＰＥＳＭＮＶＴＲＮＴＡＦＮＬＴＣＱＡＶＧＰＰＥＰＶＮＩＦＷＶＱＮＳＳＲＶＮＥＱＰＥＫＳＰＳＶＬＴＶＰＧＬＴＥＭＡＶＦＳＣＥＡＨＮＤＫＧＬＴＶＳＫＧＶＱＩＮＩＫＡＩＰＳＰＰＴＥＶＳＩＲＮＳＴＡＨＳＩＬＩＳＷＶＰＧＦＤＧＹＳＰＦＲＮＣＳＩＱＶＫＥＡＤＰＬＳＮＧＳＶＭＩＦＮＴＳＡＬＰＨＬＹＱＩＫＱＬＱＡＬＡＮＹＳＩＧＶＳＣＭＮＥＩＧＷＳＡＶＳＰＷＩＬＡＳＴＴＥＧＡＰＳＶＡＰＬＮＶＴＶＦＬＮＥＳＳＤＮＶＤＩＲＷＭＫＰＰＴＫＱＱＤＧＥＬＶＧＹＲＩＳＨＶＷＱＳＡＧＩＳＫＥＬＬＥＥＶＧＱＮＧＳＲＡＲＩＳＶＱＶＨＮＡＴＣＴＶＲＩＡＡＶＴＲＧＧＶＧＰＦＳＤＰＶＫＩＦＩＰＡＨＧＷＶＤＹＡＰＳＳＴＰＡＰＧＮＡＤＰＶＬＩＩ

Cynomolgus monkey MerTK ECD amino acid sequence (SEQ ID NO:3):
ＭＧＬＡＰＬＰＬＰＬＬＬＧＬＦＬＰＡＬＷＳＲＡＩＴＥＡＲＥＥＡＫＰＹＰＬＦＰＧＰＬＰＧＳＬＱＴＤＨＴＳＬＬＳＬＰＨＴＳＧＹＱＰＡＬＭＦＳＰＴＱＰＧＲＰＹＴＧＮＶＡＩＰＲＶＴＳＡＧＳＫＬＬＰＰＬＡＦＫＨＴＶＧＨＩＩＬＳＥＨＫＤＶＫＦＮＣＳＩＳＶＰＮＩＹＱＤＴＴＩＳＷＷＫＤＧＫＥＬＬＧＡＨＨＡＩＴＱＦＹＰＤＤＥＶＴＡＩＩＡＳＦＳＩＴＳＶＱＲＳＤＮＧＳＹＩＣＫＭＫＩＮＮＥＥＩＶＳＤＰＩＹＩＥＶＱＧＬＰＨＦＴＫＱＰＥＳＭＮＶＴＲＮＴＡＦＮＬＴＣＱＡＶＧＰＰＥＰＶＮＩＦＷＶＱＮＳＳＲＶＮＥＱＰＥＫＳＰＳＶＬＴＶＰＧＬＴＥＭＡＶＦＳＣＥＡＨＮＤＫＧＬＴＶＳＫＧＶＱＩＮＩＫＡＩＰＳＰＰＴＥＶＳＩＨＮＳＴＡＨＳＩＬＩＳＷＶＰＧＦＤＧＹＳＰＦＲＮＣＳＶＱＶＫＥＶＤＰＬＳＮＧＳＶＭＩＦＮＴＳＡＳＰＨＭＹＱＩＫＱＬＱＡＬＡＮＹＳＩＧＶＳＣＭＮＥＩＧＷＳＡＶＳＰＷＩＬＡＳＴＴＥＧＡＰＳＶＡＰＬＮＶＴＶＦＬＮＥＳＲＤＮＶＤＩＲＷＭＫＰＬＴＫＲＱＡＧＥＬＶＧＹＲＩＳＨＶＷＱＳＡＧＩＳＫＥＬＬＥＥＶＧＱＮＮＳＲＡＱＩＳＶＱＶＨＮＡＴＣＴＶＲＩＡＡＶＴＫＧＧＶＧＰＦＳＤＰＶＫＩＦＩＰＡＨＧＷＶＤＨＡＰＳＳＴＰＡＰＧＮＡＤＰＶＬＩＩ

Mouse MerTK ECD amino acid sequence (SEQ ID NO:4):
ＭＶＬＡＰＬＬＬＧＬＬＬＬＰＡＬＷＳＧＧＴＡＥＫＷＥＥＴＥＬＤＱＬＦＳＧＰＬＰＧＲＬＰＶＮＨＲＰＦＳＡＰＨＳＳＲＤＱＬＰＰＰＱＴＧＲＳＨＰＡＨＴＡＡＰＱＶＴＳＴＡＳＫＬＬＰＰＶＡＦＮＨＴＩＧＨＩＶＬＳＥＨＫＮＶＫＦＮＣＳＩＮＩＰＮＴＹＱＥＴＡＧＩＳＷＷＫＤＧＫＥＬＬＧＡＨＨＳＩＴＱＦＹＰＤＥＥＧＶＳＩＩＡＬＦＳＩＡＳＶＱＲＳＤＮＧＳＹＦＣＫＭＫＶＮＮＲＥＩＶＳＤＰＩＹＶＥＶＱＧＬＰＹＦＩＫＱＰＥＳＶＮＶＴＲＮＴＡＦＮＬＴＣＱＡＶＧＰＰＥＰＶＮＩＦＷＶＱＮＳＳＲＶＮＥＫＰＥＲＳＰＳＶＬＴＶＰＧＬＴＥＴＡＶＦＳＣＥＡＨＮＤＫＧＬＴＶＳＫＧＶＨＩＮＩＫＶＩＰＳＰＰＴＥＶＨＩＬＮＳＴＡＨＳＩＬＶＳＷＶＰＧＦＤＧＹＳＰＬＱＮＣＳＩＱＶＫＥＡＤＲＬＳＮＧＳＶＭＶＦＮＴＳＡＳＰＨＬＹＥＩＱＱＬＱＡＬＡＮＹＳＩＡＶＳＣＲＮＥＩＧＷＳＡＶＳＰＷＩＬＡＳＴＴＥＧＡＰＳＶＡＰＬＮＩＴＶＦＬＮＥＳＮＮＩＬＤＩＲＷＴＫＰＰＩＫＲＱＤＧＥＬＶＧＹＲＩＳＨＶＷＥＳＡＧＴＹＫＥＬＳＥＥＶＳＱＮＧＳＷＡＱＩＰＶＱＩＨＮＡＴＣＴＶＲＩＡＡＩＴＫＧＧＩＧＰＦＳＥＰＶＮＩＩＩＰＥＨＳＫＶＤＹＡＰＳＳＴＰＡＰＧＮＴＤＳＭ

Human, cynomolgus monkey, and mouse MerTK nucleic acid fusion constructs were transiently transfected into HEK293 cells. These recombinant fusion polypeptides were purified from cell supernatants using Mabselect resin (GE Healthcare, catalog number 17519902) according to the manufacturer's instructions. In addition, a commercially available DDDDK-tagged human MerTK fusion polypeptide (Sino Biological, Wayne, PA, Catalog No. 10298-HCCH) or a human IgG1 Fc-tagged mouse MerTK fusion protein (R&D systems, Minneapolis, MA, Catalog No. 591-MR- 100) was also used for the characterization of anti-MerTK antibodies, as described below.

Example 2 Generation of Human and Mouse MerTK Overexpressing CHO Cell Lines CHO cell lines overexpressing human and mouse MerTK were prepared as follows. Human MerTK open reading frame (ORF) clone lentiviral particles (Cat# RC215289L4V) and lentiviral particles (Cat# RC215289L4V) and Mouse MerTK ORF clone lentiviral particles (catalog number MR225392L4V) (Origene, Rockville, Md.) (both mGFP tagged) were used.

CHO cells were cultured to >80% confluence in F12-K medium (ATCC, Catalog No. ATCC30-2004) containing 10% FBS (Gibco). Cells were then dissociated with trypsin buffer (0.25% EDTA/trypsin, Gibco, cat#25200056) 24 hours prior to transduction with either human or mouse MerTK lentiviral constructs and plated in 6-well plates. were plated at 70-80% confluency. The next day, cells were incubated with lentiviral particles for 2 hours at 4°C, after which the plates were incubated at 37°C in 5% _CO2 . Two days later, puromycin for selection (Invivogen, San Diego, Calif., Cat.#ant-pr-1) was added and the selected puromycin-resistant cells were transferred to Cell Recovery Freezing Medium (Gibco, Cat. No. 12648010).

For FACS analysis of these cell lines, human MerTK-overexpressing CHO cells (CHO-huMerTK OE cells) and mouse MerTK-overexpressing CHO cells (CHO-muMerTK OE cells) generated as described above were grown at 1 to 2×10 ⁵ cells were plated in a 96-well U-bottom plate and a commercially available mouse anti-human MerTK monoclonal antibody (BioLegend, Clone: 590H11G1E3, Catalog No. 367608, San Diego, Calif.) or a commercially available rat anti-mouse MerTK monoclonal antibody. (ThermoFisher, clone: DS5MMER, catalog number 12-5751-82) for 30 minutes on ice. Cells were rinsed twice with ice-cold FACS buffer (2% FBS + PBS) and treated with APC-conjugated goat anti-mouse antibody (Jackson ImmunoResearch, West Grove, Pa., catalog number 115-606-071) or goat anti-rat antibody (Jackson ImmunoResearch). , catalog number 112-606-071) on ice for 30 minutes. After secondary antibody incubation, cells are washed with ice-cold FACS buffer and then resuspended in a final volume of 50-200 μl FACS buffer containing 0.25 μl/well of propidium iodide (BD, Catalog No. 556463). bottom. Analysis was performed using a FACS CantoII system (BD Biosciences).

The resulting human MerTK and mouse MerTK overexpressing CHO cell lines were used in subsequent studies to characterize the anti-MerTK antibodies described below.

Example 3: MerTK Expression Profile MerTK expression was detected in U937 cells (ATCC CRL-1593.2, human macrophage cell line), SK-MEL-5 cells (ATCC HTB-70, human melanoma cell line), A375 cells ( ATCC CRL-1619, human melanoma cell line), THP-1 cells (ATCC TIB-202; human monocyte-like cell line), CHO-huMerTK OE cells, human monocytes, human monocyte-derived macrophages, and human monocytes A variety of human cell types and tissues were examined, including dendritic cell-derived cells. In addition, MerTK expression was examined in human monocytes, macrophages, and dendritic cells obtained from human tumor samples, as outlined below.

Monocytes were isolated from peripheral blood mononuclear cells (PBMC) from healthy human donors using the RosetteSep monocyte isolation antibody cocktail (StemCell Technologies). Isolated human monocytes were differentiated into human macrophages with 50 ng/mL M-CSF (Peprotech) or human dendrites with 100 ng/mL GM-CSF and 100 ng/mL IL-4 (Peprotech). Differentiated into cells (DC). These human macrophages or human dendritic cells were incubated with a commercially available fluorochrome-conjugated anti-human MerTK antibody (BioLegend, clone 590H11G1E3) for 30 minutes on ice in the dark. Cells were washed twice with FACS buffer (PBS+2% FBS, 2 mM EDTA) and analysis of MerTK expression on the surface of these cells was performed using the BD FACS CantoII system.

FIG. 1 shows the results of FACS analysis of human MerTK expression in human myeloid cells (ie, dendritic cells, macrophages). As shown in Figure 1, dendritic cells (DC) and macrophages from two different human donors exhibited anti-MerTK antibody reactivity, indicating that these cells express MerTK on their cell surface. . FIG. 2 shows the results of FACS analysis of human MerTK expression in various cell lines, including A375 cells, THP-1 cells, U937 cells, SK-MEL-5 cells, and CHO-huMerTK OE cells. As shown in Figure 2, U937 cells, SK-MEL-5 cells, and CHO-huMerTK OE cells exhibited anti-MerTK antibody reactivity, indicating that these cell lines express MerTK on their cell surface. be

To analyze the expression of MerTK on various myeloid cell types (eg, monocytes, macrophages, dendritic cells) obtained from tumor samples, the following experiments were performed. Various tumor samples (from ovarian, liver, and endometrial cancer) obtained from human subjects were minced with a scalpel and transferred to GentleMACS C tubes (Miltenyi Biotec, Sunnyvale, Calif.) containing the enzyme mixture. Samples were dissociated with GentleMACS (Miltenyi Biotec) according to the manufacturer's protocol. After dissociation, cells were filtered through a 100 μm filter prior to FACS staining. The samples were then tested with Aqua Live Dead (Thermo Scientific, Catalog #L34957) and anti-human CD16 (Clone 3G8, BioLegend, Catalog #302002), anti-human CD32 (Clone AT10, Thermo Scientific, Catalog #MA1-81191), and anti-human CD16 (Clone AT10, Thermo Scientific, Catalog #MA1-81191) Stained with a mixture of human CD64 (clone 10.1, BioLegend, catalog number 305002) antibodies for 30 minutes at 4°C.

After washing with FACS buffer, the cells were then treated with the following antibodies for FACS sorting and analysis: anti-human CD45-Alexa Fluor 700 (clone HI30, BioLegend, catalog number 304024), anti-human CD3-APCCy7 (clone OKT3, BioLegend, Catalog #317342), anti-human HLA-DR-BV711 (clone L243, BioLegend, Catalog #307644), anti-human CD15-BV605 (clone W6D3, BioLegend, Catalog #323032), anti-human CD14-BUV395 (clone MoP9, BD bioscience, cat#563561), anti-human CD19-BV650 (clone HIB19, BioLegend, cat#302238), anti-human CD56-PE Dazzle 594 (clone HCD56, BioLegend, cat#318348), anti-human CD1c-PerCPCy5.5 ( Clone L161, BioLegend, Catalog No. 331514), anti-human CD206-PECy5 (clone 15-2, BioLegend, Catalog No. 321108), and anti-human MerTK-BV421 (clone 590H11G1E3, BioLegend, Catalog No. 367604) at 4°C for 30 minutes. Stained for minutes. Cells were washed with FACS buffer and acquired on a BD FACS Fortessa X20. All FACS data were analyzed using FlowJo software. Monocytes (defined and gated as CD45+CD3-CD14+), macrophages (defined and gated as CD45+CD3-CD14+CD206+), and dendritic cells (defined and gated as CD45+CD3-CD14-CD56-HLA-DR+CD1c+) were identified.

As shown in Figure 3, MerTK expression was observed by FACS analysis in monocytes, macrophages and dendritic cells obtained from peripheral blood mononuclear cells (PBMC) of healthy human subjects. MerTK expression was also observed in tumor-derived monocytes, macrophages, and dendritic cells obtained from ovarian, liver, and endometrial carcinomas from human subjects.

Taken together, this data demonstrates that MerTK expression is regulated in a variety of human cells and cell lines, monocytes, macrophages, and dendritic cells isolated from healthy human subjects, and human ovary, liver, and uterus. It was shown to be detected in monocytes, macrophages, and dendritic cells obtained from endometrial carcinoma tumor tissue.

Example 4 Generation of Anti-MerTK Hybridoma Antibodies To obtain antibodies against MerTK, the following experiments were performed to generate anti-MerTK hybridomas. BALB/c mice (Charles River Laboratories, Wilmington, Mass.) or MerTK knockout (KO) mice (Jackson Laboratories, Bar Harbor, ME) were treated with purified extracellular domain polysaccharides of human, cynomolgus monkey, and mouse MerTK with or without adjuvants. Mice were immunized twice weekly by subcutaneous or intraperitoneal injection of the peptide (obtained as described above in Example 1). A total of 8 injections were given over 4 weeks. Three days after the last injection, spleens and lymph nodes were harvested from mice for generation of hybridoma cell lines.

Lymphocytes were isolated from the spleens and lymph nodes of immunized mice and then cultured with P3X63Ag8.653 (CRL-1580, American Type Culture Collection, Rockville, Md.) or SP2/mIL-6 (CRL-2016, American Type Culture Collection, Rockville). , MD) mouse myeloma cells were fused via electrofusion (Hybrimmune, BTX, Holliston, Mass.) at 37° C., 5% CO ₂ in Clonacell-HY Medium C (STEMCELL Technologies, Vancouver, BC, Canada). , catalog number 03803) overnight. The next day, the fused cells were centrifuged and resuspended in 10 ml ClonaCell-HY Medium C containing anti-mouse IgG Fc-FITC (Jackson ImmunoResearch, West Grove, Pa.) and added to 90 ml methylcellulose-based ClonaCell-HY containing HAT components. Gently mixed with Medium D medium (STEMCELL Technologies, Catalog No. 03804). These cells were plated in Nunc OmniTrays (Thermo Fisher Scientific, Rochester, NY) and grown at 37°C, 5% _CO2 for 7 days. Fluorescent colonies were then selected and transferred to 96-well plates containing Clonacell-HY Medium E (STEMCELL Technologies, Catalog No. 03805) using a Clonepix 2 (Molecular Devices, Sunnyvale, Calif.). In total, 1,728 IgG-secreting hybridoma clones were selected. After 6 days of culture, tissue culture supernatants from hybridomas were screened by FACS analysis for specificity for binding human or mouse MerTK as described below.

Example 5 Screening of Anti-MerTK Antibody Hybridoma Supernatants by FACS Hybridoma culture supernatants from 1,728 hybridomas obtained as described above were transfected into CHO cells stably overexpressing human MerTK (CHO-huMerTK OE). cells) or CHO cells stably overexpressing mouse MerTK (CHO-muMerTK OE cells) (generated as described above), as well as CHO parental cells, U937 cells (ATCC CRL-1593.2), SK-MEL -5 cells (ATCC HTB-70) (endogenously expressing human MerTK), J774A. 1 cells (ATCC TIB-67), which endogenously express mouse MerTK, and A375 cells (ATCC CRL-1619) were screened for their ability to bind MerTK. In these experiments, THP-1 cells that do not express or minimally express MerTK (ATCC TIB-202) served as negative control cells that do not express MerTK.

For screening of hybridoma cell culture supernatants, a multiplexed FACS experimental design was utilized to identify binding of anti-MerTK antibodies to these multiple cell lines. Briefly, cells were stained with various concentrations and combinations of the CellTrace cell proliferation dyes CFSE and Violet (ThermoFisher, Cat#C34554 and Cat#34557, respectively) to create unique barcoded cell populations. 70,000 cells of each barcoded cell type were aliquoted into a 96-well U-bottomed plate and 50 μl of hybridoma cell culture supernatant or 5 μg/ml of commercially available purified mouse anti-human MerTK monoclonal antibody (BioLegend, Catalog #367602). , serving as positive anti-MerTK antibodies) for 30 min on ice. After incubating this primary anti-MerTK hybridoma supernatant with these various MerTK-expressing cell types, the supernatant was removed by centrifugation and the cells were washed twice with 175 μl of ice-cold FACS buffer (PBS+1% FBS+2 mM EDTA), These cells were then further incubated on ice with anti-mouse IgG Fc-allophycocyanin (APC) (Jackson Labs, catalog number 115-136-071) (diluted 1:1000) for 20 minutes. After this secondary antibody incubation, the cells were washed twice again with ice-cold FACS buffer and resuspended in a final volume of 30 μl FACS buffer containing 0.25 μl/well of propidium iodide (BD Biosciences, catalog number 556463). Suspended. Binding strength in cells was analyzed using a FACS Canto system (BD Biosciences) with a sorting gate subtracted to exclude dead (ie propidium iodide positive) cells. A ratio of APC mean fluorescence intensity (MFI) for each barcoded cell population was determined for each anti-MerTK hybridoma supernatant tested.

From the screening of this particular hybridoma supernatant, binding to cells stably overexpressing or endogenously expressing human or mouse MerTK (measured by MFI A total of 308 anti-MerTK hybridoma clones were identified that exhibited more than a 2-fold difference in . Anti-MerTK antibodies identified using this screen were further characterized as follows.

Example 6 Screening of Anti-MerTK Antibody Hybridoma Supernatants by Recombinant MerTK Protein Binding Assay Hybridoma culture supernatants from 1,728 hybridomas obtained as described above were screened for binding to an irrelevant His-tagged control protein. In comparison, they were screened for their ability to bind poly-His-tagged human, cynomolgus monkey, and mouse MerTK (prepared as described above in Example 1). Briefly, 96-well polystyrene plates were coated with 1 μg/ml human, cynomolgus monkey, or mouse poly-His-tagged MerTK polypeptide in coating buffer (0.05 M carbonate buffer, pH 9.6, Sigma, catalog number C3041). Coated overnight at 4°C. The coated plates were then blocked with ELISA diluent (PBS + 0.5% BSA + 0.05% Tween® 20) for 1 hour and washed with 300 μl PBST (PBS + 0.05% Tween® 20, Thermo 28352) for 3 hours. washed twice. These hybridoma cell culture supernatants or two commercially available purified mouse anti-human MerTK monoclonal antibodies (BioLegend Catalog No. 367602, R&D Catalog No. MAB8912) were added to each well (50 μl/well). After 30 minutes of incubation (room temperature, shaking), the plates were washed 3 times with 300 μl of PBST. Anti-mouse IgG Fc-HRP (Jackson Immunoresearch, Catalog #115-035-071) secondary antibody was diluted 1:5000 in ELISA diluent and added to each well at 50 μl/well and incubated for 30 minutes at room temperature with shaking. Incubate for 1 minute. After the last set of washes (3×300 μl in PBST), 50 μl/well of TMB substrate (BioFx, Catalog No. TMBW-1000-01) was added to the wells. The reaction was then quenched after 5-10 minutes with 50 μl/well of stop solution (Biofx, Cat# BSTP-1000-01). Quenched reaction wells were detected for absorbance at 650 nm using GEN5 2.04 software on a BioTek Synergy microplate reader. From this hybridoma supernatant screen, a total of 326 anti-MerTK hybridoma clones were identified that exhibited greater than 10-fold difference in binding to recombinant MerTK compared to background. Anti-MerTK antibodies identified using this screen were further characterized as follows.

Example 7: MerTK Ligand Gas6 and Ligand ProS Blocking Assay Using Anti-MerTK Hybridoma Supernatant The anti-MerTK antibody hybridoma supernatant identified above was tested for its ability to block the binding of human Gas6 ligand to human MerTK and/or or assessed by ELISA for their ability to block binding of human ProS ligand. Briefly, a rabbit anti-human IgG antibody (Jackson ImmunoResearch, Catalog No. 309-005-008) was coated onto high protein binding plates at 2 μg/ml overnight at 4°C. After washing three times with PBS containing 0.05% Tween® 20, PBS containing 5% BSA was added for 1 hour. Recombinant human MerTK-human Fc chimeric protein (R&D systems, catalog number 391-MR-100) was added at 2 μg/ml for 1 hour and the plate was washed followed by 40 μl of anti-MerTK hybridoma supernatant and 40 μl of His-tag conjugate. Recombinant Gas6 (R&D systems, Catalog No. 885-GSB-050) was added at 3 μg/ml or His-tag conjugated recombinant ProS (R&D systems, Catalog No. 9489-PS-100) at 20 μg/ml. After an additional hour of incubation, the plates were washed and incubated with HRP-conjugated anti-6xHis-tagged antibody (Abcam, Cambridge, Mass., catalog number ab1187) for one hour. The plate was then washed and the HRP substrate TMB was added to develop the plate. The reaction was stopped by adding 50 μl of 2N H ₂ SO ₄ and OD was measured using a spectrophotometer (BioTek).

A total of 308 anti-MerTK hybridoma supernatant clones were screened for their ability to block Gas6 ligand binding and/or block ProS ligand binding to MerTK. Twenty-nine (29) anti-MerTK hybridoma clones blocked binding of both ProS and Gas6 ligands to recombinant human MerTK protein. One hundred forty-five (145) anti-MerTK hybridoma clones blocked only ProS ligand binding to human MerTK protein, but not Gas6 ligand binding to recombinant human MerTK protein. The remainder of the 308 anti-MerTK hybridoma clones screened in this assay did not block binding of either ProS or Gas6 ligands to recombinant human MerTK protein in this assay. These hybridoma supernatants were further characterized for their ability to block efferocytosis by phagocytic cells, as described below.

Example 8: Efferocytosis Blocking Assay Using Anti-MerTK Hybridoma Supernatants The anti-MerTK antibody hybridoma supernatants identified above as positive for MerTK binding reactivity were tested for efferocytosis by human macrophages, as described below. evaluated for their ability to block. Human macrophages were differentiated from human monocytes in the presence of human M-CSF for 7 days. Macrophages were harvested (by scraping), resuspended in PBS and plated at 5 x ¹⁰⁴ cells/well in 96-well plates. After starving the cells for 1 hour, anti-MerTK hybridoma supernatant was added to each well for 30 minutes at 37°C. Jurkat cells were treated with 1 μM staurosporine (SigmaAldrich) for 3 hours at 37° C. (to induce apoptosis) and labeled with pHrodo (ThermoFisher) for 30 minutes at room temperature. After washing with PBS, pHrodo-labeled Jurkat cells were added to each well at a 1:4 ratio (1 macrophage cell to 4 Jurkat cells) for 1 hour. After washing the plates with PBS, cells were stained with APC-conjugated anti-human CD14 for 30 minutes on ice in the dark. Cells were then washed twice with FACS buffer (PBS + 2% FBS) and flow cytometry was performed on a BD FACS CantoII. Data were analyzed using FlowJo software. Macrophages capable of efferocytosis engulf labeled apoptotic Jurkat cells, which are subsequently detected, whereas macrophages whose efferocytosis execution is blocked engulf labeled apoptotic Jurkat cells. Shows reduced entrainment.

In these experiments, efferocytosis-positive macrophages were identified by setting pHrodo CD14 double-positive cells as an analysis gate and applying this strict gate to all samples. A baseline efferocytosis level was established using macrophages cultured in medium alone, which was set at 100% efferocytosis activity. Relative efferocytosis levels were calculated as the percentage of efferocytosis observed in cells treated with medium alone compared to that observed in cells treated with anti-MerTK hybridoma supernatant. In these experiments the following additional anti-MerTK antibodies were used: mouse anti-human MerTK antibody H1 (BioLegend, clone ID: 590H11G1E3, mouse IgG1) and human anti-human MerTK antibody M6 (as disclosed in WO2016/106221). .

Tables 1 and 2 below show the results of these efferocytosis experiments as % efferocytosis (medium alone set at 100% efferocytosis). In Table 1 below, exemplary hybridoma supernatants tested are shown on the left and labeled as hybridoma supernatant ID numbers. These supernatants were derived from hybridoma clones identified from immunization of wild-type BALB/c mice. In Table 2 below, exemplary hybridoma supernatants tested are shown on the left and labeled as hybridoma supernatant ID numbers. These supernatants were derived from hybridoma clones identified from immunizations of MerTK KO mice. In both Tables 1 and 2, Antibody ID refers to an anti-MerTK antibody of the present disclosure that was selected for further characterization and thus given the name of the particular anti-MerTK antibody as indicated. Columns 3, 4 and 5 (“donor” identification numbers) show percent efferocytosis relative to media treatment alone. Note that no significant change in efferocytosis was observed in cells treated with isotype control mouse IgG1 antibody compared to macrophage efferocytosis in the absence of antibody (medium treatment alone). .

Tables 1 and 2 show the percent efferocytosis by human macrophages from different donors, with media alone (no antibody added) set at 100% efferocytosis in both tables. Although the degree of efferocytosis-blocking activity by various anti-MerTK antibody hybridoma supernatants differed in macrophages obtained from each donor, the efferocytosis-blocking propensity of anti-MerTK antibodies was consistent among macrophages from different donors. Was. As shown in Tables 1 and 2 above, anti-MerTK hybridoma supernatants of the present disclosure reduced efferocytosis by human macrophages to varying degrees (e.g., reduced efferocytosis by about 50% to 85%). ). These results indicated that anti-MerTK antibodies obtained as described herein are effective in reducing or blocking efferocytosis by phagocytic cells.

Example 9: Molecular Cloning of Anti-MerTK Antibodies Anti-MerTK antibodies from the hybridomas described above were subcloned as follows. After harvesting 5×10 ⁵ hybridoma cells and washing with PBS, the cell pellet was quickly frozen on dry ice and stored at -20°C. Total RNA was extracted using the RNeasy Mini kit (QIAGEN, catalog number 74104) according to the manufacturer's protocol. cDNA was generated using Clontech's SMARTerRACE 5'/3' kit (Takara Bio USA, catalog number 634859) according to the manufacturer's protocol. The variable heavy and light chain immunoglobulin regions were cloned separately by touchdown PCR using the 5'UPM primer provided in the RACE kit and reverse primers recognizing the heavy and light chain constant regions. The resulting PCR product was purified, ligated into the pCR2.1-TOPO cloning vector (TOPO TA cloning kit, Invitrogen catalog number 450641), and transformed into Escherichia coli (E. coli) cells. Transformed colonies were isolated and their variable heavy chain (VH) and variable light chain (VL) nucleic acids were sequenced for each corresponding hybridoma cell line. Following sequencing, the variable heavy and light chain regions were amplified by PCR using primers containing endonuclease restriction enzyme recognition sites, followed by human IgG1-Fc-LALAPS (amino acid substitution L234A according to EU numbering, L235A, and human IgG1 Fc (including P331S) and IgG kappa were subcloned into the pLEV-123 (LakePharma, San Carlos, Calif.) mammalian expression vector.

The amino acid sequences of the variable heavy and variable light chains of the anti-MerTK antibodies of this disclosure are shown in Table 3 below. In Table 3 the CDR/HVR sequences (according to Kabat) are underlined.

The CDR sequences according to Kabat for the anti-MerTK antibodies of this disclosure are shown below in Table 4 (heavy chain) and Table 5 (light chain).

Example 10: Production of Anti-MerTK Antibodies Anti-MerTK hybridoma clones were cultured in serum-free hybridoma medium and anti-MerTK antibodies in the supernatant were detected on the Hamilton STAR platform using a protein A chip (Phynexus Inc, San Jose, Calif.). (Hamilton Company, Reno, NV). Anti-MerTK antibodies have also been produced by cloning the variable gene regions obtained from the hybridomas directly into a recombinant expression plasmid for the production of chimeric antibodies containing a human Fc domain (human IgG1 containing the LALAPS amino acid substitutions described above). was done. HEK293 cells were seeded into shake flasks using the Tuna293™ process (LakePharma, San Carlos, Calif.) and grown using serum-free chemically defined media. Expression plasmids were transiently transfected into these cells and culture supernatants were harvested after 7 days. After clarification by centrifugation and filtration, the anti-MerTK antibody in the supernatant was purified by Protein A chromatography.

Example 11 Blocking Efferocytosis by Recombinant Anti-MerTK Antibodies The ability of anti-MerTK antibodies of the disclosure to block efferocytosis by phagocytes (eg, human macrophages or mouse bone marrow-derived macrophages) was evaluated as follows. Human macrophages were differentiated from human monocytes in the presence of human M-CSF for 7 days. Mouse bone marrow-derived macrophages were differentiated from mouse bone marrow cells for 7 days in the presence of mouse M-CSF (Peprotech, catalog number 315-02). After 7 days, human and mouse macrophages were harvested (by scraping), resuspended in PBS and plated at 5 x ¹⁰⁴ cells/well in 96-well plates. To determine the IC50 for efferocytosis, cells were starved for 1 hour before adding 10 μl of recombinant anti-MerTK antibody to each well for 30 minutes at 37°C. For other studies described herein, recombinant anti-MerTK antibody was titrated to a final concentration range of 66.6 nM to 4 pM, then each serially diluted antibody was added to each well for 30 minutes at 37°C.

Jurkat cells were treated with 1 μM staurosporine (SigmaAldrich) for 3 hours at 37° C. (to induce apoptosis) and labeled with pHrodo (ThermoFisher) for 30 minutes at room temperature. After washing with PBS, pHrodo-labeled Jurkat cells were added to each well at a 1:4 ratio (1 macrophage:4 Jurkat cells) for 1 hour. After washing the plates with PBS, cells were stained with APC-conjugated anti-human CD14 or anti-mouse CD11b for 30 minutes on ice in the dark. Cells were then washed twice with FACS buffer (PBS + 2% FBS) and flow cytometry was performed on a BD FACS Canto II. Data were analyzed using FlowJo software.

In addition to the anti-MerTK antibodies of the present disclosure, the following anti-MerTK antibodies were also used in these efferocytosis studies: rat anti-mouse MerTK antibody DS5MMER (eBioscience, clone ID DS5MMER, rat IgG2a), mouse anti-human MerTK antibody. H1 (BioLegend clone ID: 590H11G1E3, mouse IgG1), mouse anti-human MerTK antibody H2 (R & D systems, clone ID: 125518, mouse IgG2b), mouse anti-human MerTK antibody H3 (R & D systems, clone ID125508, mouse IgG2b), mouse anti human MerTK antibody H6 (eBioscience, clone ID: A3KCAT, mouse IgG1), mouse anti-human MerTK antibody H7 (Sino Biological, clone ID: 09, mouse IgG2b), human anti-human MerTK antibody M6 (disclosed in WO2016/106221 huIgG1 LALAPS), and human anti-human MerTK antibody CDX AB2000-A7 (disclosed in WO2019/084307, huIgG1).

In these experiments, efferocytosis-positive macrophages were identified by setting pHrodo CD14 double-positive cells as an analysis gate and applying this strict gate to all samples. A baseline efferocytosis level was established using macrophages cultured in medium alone, which was set at 100% efferocytosis activity. Relative efferocytosis levels were calculated as the percentage of efferocytosis observed in cells treated with medium alone compared to that observed in cells treated with anti-MerTK antibody.

No significant changes in efferocytosis were observed with isotype control human IgG1 LALAPS, mouse IgG1, or mouse IgG2b compared to macrophages in the absence of antibody (medium alone treatment).

Efferocytosis blocking studies were performed by adding 10 μg/ml of recombinant anti-MerTK of the present disclosure to macrophages. Tables 6 and 7 show % efferocytosis of anti-MerTK antibodies of the present disclosure with respect to efferocytosis activity by macrophages obtained from various human donors.

As shown in Tables 6 and 7 above, the anti-MerTK antibodies of the disclosure reduced or reduced efferocytosis by human macrophages (eg, reduced efferocytosis by about 50% to about 98%). Efferocytosis-blocking activity by anti-MerTK antibodies varied between donors, but a general trend was observed for each antibody.

Figures 4 and 5 show efferocytosis blocking results of exemplary anti-MerTK antibodies of the present disclosure. As shown in FIG. 4, the anti-MerTK antibodies MTK-06, MTK-10, MTK-15, MTK-16, and MTK-21 of the disclosure dose-dependently inhibited efferocytosis of apoptotic cells by human macrophages. effectively hindered. These results indicated that the anti-MerTK antibodies of the present disclosure are effective in reducing or reducing efferocytotic activity by human macrophages.

As shown in FIG. 5, the anti-MerTK antibodies MTK-24, MTK-29, MTK-31, and MTK-33 of the present disclosure inhibited efferocytosis of apoptotic cells by mouse bone marrow-derived macrophages in a dose-dependent manner. inhibited. These results indicated that the anti-MerTK antibodies of the present disclosure are effective in reducing or reducing efferocytotic activity by mouse bone marrow-derived macrophages.

Table 8 below shows the IC50 values of the anti-MerTK antibodies of the present disclosure for reducing or reducing efferocytosis by human macrophages at various IC50 values. As shown in Table 8 above, the anti-MerTK antibodies of the present disclosure reduced or reduced efferocytosis by human macrophages with an IC50 range of about 1.2 nM to about 28 nM.

Tables 9 and 10 show the IC50 values of anti-MerTK antibodies of the present disclosure for efferocytosis activity by murine macrophages and macrophages obtained from various human donors.

As shown in Tables 8, 9, and 10 above, the anti-MerTK antibodies of the present disclosure were effective in reducing efferocytosis by human and mouse macrophages. Furthermore, these results indicated that the anti-MerTK antibodies of the present disclosure reduced efferocytosis by human macrophages with an IC50 of about 0.13 nM to about 30 nM.

Example 12: Anti-MerTK Antibodies Bind to SK-MEL-5 Cells and CHO-muMerTK OE Cells Recombinant anti-human MerTK antibodies of the disclosure bind to endogenously expressed human MerTK and To determine whether it binds to CHO cells overexpressing mouse MerTK (CHO-muMerTK OE cells), the following experiment was performed. SK-MEL-5 cells and CHO-muMerTK OE cells were plated at 40,000 cells/well. Anti-MerTK antibodies were titrated to final concentrations ranging from 66.6 nM to 4 pM and then added to the cells. After 30 minutes on ice, the cells were washed and then incubated with APC-conjugated mouse anti-human kappa antibody (Southern Biotech cat #9230-11, Birmingham, Ala.) and viability dye (Life Technologies) in the presence of Fc blocking solution. , stained on ice for 30 minutes, then washed twice with cold FACS buffer (PBS with 2% FBS). Cells were fixed with PBS containing 4% paraformaldehyde. Stained cells were acquired on a BD FACS Canto II cytometer, mean fluorescence intensity (MFI) was calculated with FlowJo software, and K values were calculated with Prism software. Kd values in these results, similar to EC50 values, are calculated by Prism software from data generated by FACS analysis. A lower Kd value indicates higher binding of the antibody to the cell.

FIG. 6. Anti-human MerTK antibodies MTK-06, MTK-10, MTK-11, MTK-13, MTK-15, and MTK-16 dose dependent on endogenously expressed MerTK in SK-MEL-5. It shows that the

Tables 11, 12, and 13 below provide Kd values from FACS analysis of anti-MerTK antibodies binding to SK-MEL-5 cells (Tables 11 and 12) and CHO-muMerTK-OE cells (Table 13). show.

Anti-MerTK antibodies bind to SK-MEL-5 or CHO-muMerTK overexpressing cells in a dose dependent manner with Kd values in the picomolar to nanomolar range. Anti-MerTK antibodies such as MTK-06 and MTK-12 bound better to SK-MEL-5 compared to the M6 antibody. The data in Tables 11, 12, and 13 above demonstrate that the anti-MerTK antibodies MTK-24, MTK-29, MTK-30, MTK-31, and MTK-33 are endogenously expressed in human SK-MEL-5 cells. It has also been shown to bind to human MerTK and mouse MerTK recombinantly expressed in CHO cells.

Example 13: Blocking the Binding of Ligand Gas6 and Ligand ProS to MerTK with Anti-MerTK Antibodies
To determine the ligand blocking activity of the anti-MerTK antibodies of the present disclosure, a ligand blocking assay was performed to determine whether a given anti-MerTK antibody blocks binding of ligand Gas6 or ligand ProS to human MerTK.

A rabbit anti-human IgG polyclonal antibody (Jackson ImmunoResearch, catalog number 309-005-008) was captured overnight at 2 μg/ml to high protein binding plates at 4°C. After washing three times with PBS containing 0.05% Tween® 20, PBS containing 5% BSA was added for 1 hour. Recombinant human MerTK human Fc chimeric protein (R&D systems, catalog number 391-MR-100) was added at 2 μg/ml for 1 hour, after which the plates were washed. Anti-MerTK antibody was titrated to a final concentration range of 66.6 nM to 4 pM, followed by 40 μl of serially diluted antibody and 40 μl of His-tag conjugated recombinant Gas6 protein (R&D systems, cat#885-GSB-050) at 3 μg/ml. , or His-tag conjugated recombinant ProS protein (R&D systems, catalog number 9489-PS-100) at 20 μg/ml. After an additional 1 hour incubation, plates were washed and incubated with HRP-conjugated anti-6xHis tag antibody (Abcam, cat#ab1187) for 1 hour. Plates were then washed and developed using HRP substrate (TMB). After a sufficient color change was observed, the reaction was stopped by adding 50 μl of 2N H ₂ SO ₄ and OD was measured using a spectrophotometer (BioTek).

FIG. 7 shows that exemplary anti-MerTK antibodies of the disclosure (MTK-07, MTK-16, and MTK-21) dose-dependently inhibited (eg, blocked) binding of Gas6 ligand to human MerTK. indicates As shown in FIG. 7, the anti-MerTK antibodies MTK-06, MTK-08, MTK-09, and MTK-15 did not block the binding of Gas6 ligand to human MerTK.

FIG. 8 shows exemplary anti-MerTK antibodies of the present disclosure (MTK-03, MTK-07, MTK-09, MTK-17, MTK-18, and MTK-23) inhibit binding of ProS ligand to human MerTK. Inhibition (eg, block) is shown in a dose-dependent manner.

From these experiments, IC50 values [nM] were determined using OD450 values obtained from dose-response curves analyzed with Prism software. Tables 14 and 15 show IC50 values identified for blocking of Gas6 and ProS ligand binding to MerTK by anti-MerTK antibodies. Although the anti-MerTK antibody MTK-22 did not block either Gas6 or ProS ligand binding to MerTK, the anti-MerTK antibody MTK-22 was effective in reducing efferocytosis as shown in the Examples above. rice field. Dashes indicate no significant blocking. "na" indicates that there is no applicable data.

In these studies, thirty-five (35) anti-MerTK antibodies of the present disclosure were examined for their ability to block Gas6 ligand binding and/or ProS ligand binding to human MerTK. The anti-MerTK antibodies of the present disclosure of nineteen (19) (MTK-03, MTK-07, MTK-10, MTK-12, MTK-13, MTK-16, MTK-17, MTK-18, MTK-20, MTK -21, MTK-24, MTK-25, MTK-26, MTK-27, MTK-30, MTK-31, MTK-33, MTK-35, and MTK-36) are ProS ligands and Blocking the binding of both Gas6 ligands (referred to herein as ProS/Gas6 double blockers), fifteen (15) anti-MerTK antibodies of the present disclosure (MTK-01, MTK-02, MTK-04, MTK- 05, MTK-06, MTK-08, MTK-09, MTK-11, MTK-14, MTK-15, MTK-19, MTK-23, MTK-28, MTK-29, MTK-32) are recombinant human It blocked ProS ligand binding (but not Gas6 ligand binding) to MerTK (referred to herein as ProS-specific blockers). Although the anti-MerTK antibody MTK-22 did not block ProS or Gas6 ligand binding to recombinant human MerTK protein as measured in this assay, the anti-MerTK antibody MTK-22, as described in the Examples above, It was effective in reducing efferocytosis. Anti-MerTK antibody M6 and anti-MerTK antibody CDX AB2000-A7 showed blocking of ProS and Gas6 ligands. Anti-MerTK antibody H1 and anti-MerTK antibody H2 showed only ProS ligand blocking and neither of these antibodies showed Gas6 ligand blocking.

These results suggested that the anti-MerTK antibodies of the present disclosure can selectively modulate Gas6 and ProS binding to MerTK and selectively modulate Gas6 and ProS activity.

Example 14: Binding Kinetics of Anti-MerTK Antibodies Binding kinetics of human anti-MerTK IgG1 LALAPS antibodies of the disclosure to human, cynomolgus monkey, and mouse MerTK were measured using a Carterra LSA instrument (Carterra, Salt Lake City, UT). evaluated. Briefly, anti-MerTK antibody was prepared at 300 μl/well by diluting to 10 μg/ml with 10 mM acetic acid, pH 4.25 (Carterra). HC200M sensor chips (Carterra) were reconstituted with 1:1:1 mixed 100 mM MES pH 5.5, 100 mM sulfo-NHS, 400 mM EDC (all MES pH 5.5, 100 μl of each mixed in a vial) was injected for 7 minutes to activate just before running the assay. After switching to the multi-channel array flow cell, the antibody was injected for 15 minutes into the activated chip of the 96-spot array. Remaining unconjugated active groups on the chip were then blocked by injecting 1 M ethanolamine pH 8.5 (Carterra) for 7 minutes using a single-channel flow cell.

After priming with running buffer (HBS-TE, Carterra) containing 0.5 mg/ml BSA (Sigma), immobilized anti-MerTK antibody was applied to extracellular recombinant MerTK including human, cynomolgus monkey, and mouse orthologues described above. They were examined for their ability to bind several forms of domains. Affinity estimates were generated by injecting each analyte over the antibody array using a single-channel flow cell. MerTK analytes were diluted in running buffer to 33.3, 100, and 300 nM and injected sequentially from lowest to highest concentration without regeneration. Two buffer blanks were run between each series (one per series). Data were processed and analyzed using NextGenKIT high-throughput kinetic analysis software (Carterra).

Equilibrium dissociation constants (K _D ) were then calculated from the fitted association and dissociation rate constants (k-on and k-off) for the anti-MerTK antibodies of the disclosure. Binding kinetic analysis was also performed with anti-MerTK antibodies H1 (BioLegend, clone ID: 590H11G1E3), H2 (R&D systems, clone ID: 125518), M6 (WO2016/106221), and CDX AB2000-A7 hIgG1 (WO2019/084307). rice field. These _KD values are summarized in Table 16 below.

These results indicated that the anti-MerTK antibodies of the present disclosure exhibit varying affinities and cross-species binding specificities for MerTK. In particular, the affinities of the anti-MerTK antibodies of the disclosure for binding to human MerTK ranged from 1.4 nm to 81 nM, and the affinities of the anti-MerTK antibodies of the disclosure for binding to cynomolgus monkey MerTK ranged from 1.6 nm to 107 nM. And the affinities of the anti-MerTK antibodies of the disclosure for binding to mouse MerTK ranged from 30 nM to 186 nM.

Example 15 Cross-Reactivity of Anti-MerTK Antibodies to Human, Cynomolgus Monkey, and Mouse MerTK Cross-species cross-reactivity of the anti-MerTK antibodies of the disclosure was determined from the binding kinetic analysis data described above. The results of the cross-species binding cross-reactivity assay are shown in Table 17 below.

These binding experiments showed that the majority of the anti-MerTK antibodies of this disclosure tested exhibited binding cross-reactivity to both human and cynomolgus monkey MerTK (MTK-01, MTK-02, MTK-03 , MTK-04, MTK-06, MTK-07, MTK-08, MTK-09, MTK-10, MTK-11, MTK-13, MTK-14, MTK-15, MTK-16, MTK-17, MTK -18, MTK-19, MTK-20, MTK-21, MTK-22, MTK-24, MTK-26, MTK-27, MTK-28, MTK-30, MTK-31, MTK-32, MTK-33 , MTK-34, MTK-35, and MTK-36). Two anti-MerTK antibodies of the present disclosure showed specific binding only to human MerTK and no binding to cynomolgus monkey MerTK or mouse MerTK (antibodies MTK-05 and MTK-12). Six anti-MerTK antibodies of the disclosure tested showed cross-reactivity to both human and mouse MerTK (MTK-19, MTK-24, MTK-30, MTK-31, MTK-32, and MTK-33 ). Six anti-MerTK antibodies of the disclosure tested showed cross-reactivity to human, cynomolgus monkey, and mouse MerTK (MTK-19, MTK-24, MTK-30, MTK-31, MTK-32, and MTK- 33). Furthermore, Example 12 above showed that the anti-MerTK antibodies MTK-24 and MTK-29 also bind to human and mouse MerTK.

Example 16: Epitope Binning Analysis of Anti-MerTK Antibodies Epitope binning analysis was performed on anti-MerTK antibodies of the disclosure by performing a tandem injection approach using a Carterra LSA instrument (Carterra, Salt Lake City, UT). went. Briefly, hybridoma-purified murine anti-MerTK antibodies of the present disclosure, anti-MerTK antibodies H1, H2, H3, H6, and M6, and anti-his IgG were added to 15 μg/ml in 10 mM acetic acid, pH 4.75 (Carterra) at 300 μl/well. diluted with A second set of samples was prepared by diluting the antibody 5-fold to 3 μg/ml in the same buffer. HC200M sensor chips (Carterra) were injected with 100 mM MES pH 5.5, 100 mM sulfo-NHS, 400 mM EDC (as above) mixed 1:1:1 for 7 minutes using a single channel flow cell. activated. After switching to the multi-channel array flow cell, a 15 μg/ml dilution of antibody was injected for 15 minutes onto the activated chip of the 96-spot array. A second array was printed by injecting a 3 μg/ml dilution of antibody onto a second 96-spot array. Remaining unconjugated active groups on the chip were then blocked by injecting 1 M ethanolamine pH 8.5 (Carterra) over the entire surface of the chip for 7 minutes using a single-channel flow cell.

After priming with running buffer (HBS-TE, Carterra) containing 0.5 mg/ml BSA (Sigma), immobilized antibodies were examined for their ability to bind recombinant human MerTK extracellular domain. Bound MerTK was removed with two 30 sec injections of 0.425% phosphoric acid (Carterra). At each cycle, MerTK was injected over the chip, followed by test antibody diluted to 30 μg/ml in running buffer. Data were processed and analyzed using epitope high-throughput binning analysis software (Carterra). Antibodies that were able to bind to the antigen captured by the immobilized antibody were designated as 'sandwich' or 'paired' antibodies, and these antibodies were assigned to different epitope bins than the immobilized antibody. A matrix of paired and unpaired antibodies was constructed from the binding results of these experiments, allowing the generation of an anti-MerTK antibody epitope bin landscape.

Epitope bins identified from these studies on anti-MerTK antibodies are summarized in FIG. These results indicated that most of the ProS ligand-specific blockers belonged to the bin 1 group, except for MTK-19, which is contained in bin 2. The ProS-specific blocker of anti-MerTK control antibody H1 belongs to bin 1 group. All ProS/Gas6 double blockers belong to bin 3 to bin 8 groups. Some antibodies recognize partially adjacent epitopes, resulting in overlapping binning. For example, MTK-03 and MTK-07 have the most widely overlapping epitopes in bin 3, bin 5, bin 6, and bin 8. The ProS/Gas6 double blocker of the anti-MerTK control antibody M6 belongs to bin 4 and H6 belongs to the bin 5 group. These results suggest that ProS and Gas6 may bind to different epitopes or regions of MerTK.

Example 17 Inhibition of Tumor Growth In Vivo by Anti-MerTK Antibodies To determine the effect of anti-MerTK antibodies on tumor growth, an in vivo efficacy study was performed using the MC38 murine syngeneic colon cancer model. MC38 cells were resuspended in PBS at 5×10 ⁶ cells/ml. 100 μl of cells were injected subcutaneously into the shaved right flank of C57BL/6 mice. When tumor size reached a volume of approximately 60-100 mm ³ , mice were randomized to treatment (N=10) or control groups based on tumor volume. Treatment groups received 10 mg/kg control antibody, 3 mg/kg anti-PDL1 (clone: BM1) alone, 10 mg/kg anti-MerTK antibody DS5MMER alone, or 3 mg/kg anti-PDL1 plus anti-MerTK antibody DS5MMER together. bottom. After initiation of antibody administration, mice were weighed and tumor volumes were measured twice weekly using caliber. The study was terminated when the tumors of the control group reached approximately 2000 mm ³ .

Figures 10A and 10B show that anti-MerTK antibody DS5MMER treatment alone or in combination with anti-PDL1 antibody reduced tumor growth in vivo. These results demonstrate that anti-MerTK antibodies are effective in reducing tumor volume and slowing tumor growth in vivo. These results further demonstrated that anti-MerTK antibody reduced tumor volume and growth to a greater extent when used in combination with anti-PD-L1 antibody compared to either antibody alone.

Example 18: Modulation of Inflammatory Cytokine Production The effect of anti-MerTK antibodies on inflammatory cytokine production in myeloid cells was investigated as follows. To generate monocyte-derived macrophages and dendritic cells, human primary monocytes were purified from heparinized human blood (Blood Centers of the Pacific) using a RosetteSep Human Monocyte Enrichment Cocktail (STEMCELL Technologies) at the manufacturer's Isolated according to protocol. Monocytes were treated with 10% fetal bovine serum (Hyclone) and 50 ng/mL IL-4 and GM-CSF (Peprotech) to induce dendritic cell differentiation or 50 ng/mL to induce macrophage differentiation. of RPMI (Invitrogen) containing M-CSF (Biolegend). After 6-7 days, dendritic cells or macrophages were harvested by scraping the cells. Macrophages or dendritic cells were plated in 96-well plates at 5 x ¹⁰⁴ cells/well and cultured overnight at 37°C with 10 μg/mL antibody. The next day, supernatants were collected and 13-plex human inflammatory chemokines and human macrophage/microglia LEGENDplex bead arrays (BioLegend) were used according to the manufacturer's protocol. All samples were run on a BD FACS Canto II and analysis was performed using LEGENDplex analysis software (BioLegend).

Figures 11A, 11B, 11C, and 11D show MCP1 (CCL2), MIP-1α from human macrophages after overnight treatment with anti-MerTK antibodies MTK-15, MTK-16, MTK-29, or MTK-33, respectively. (CCL3), MIP-1β (CCL4), and changes in TNF levels. Anti-MerTK antibodies MTK-16 and MTK-29 significantly increased levels of MCP1, MIP-1α, MIP-1β, and TNF in human macrophages. Levels of MCP1 were significantly increased in response to the anti-MerTK antibody MTK-33 compared to that observed after treatment with control antibody. These results indicate that the anti-MerTK antibodies MTK-15, MTK-16, MTK-29, and MTK-33 induce inflammatory chemokine or cytokine production in human macrophages in a MerTK-dependent manner. These results further demonstrate that the anti-MerTK antibodies of the disclosure are effective in increasing pro-inflammatory cytokines and chemokines in myeloid cells, and that the anti-MerTK antibodies of the disclosure are effective in increasing the activity of myeloid cells (e.g., macrophages). It shows that it is effective for These results also demonstrated that the anti-MerTK antibodies of the present disclosure are effective in increasing M1-like macrophage polarization and thus mediating anti-tumor immunity.

Example 19 Effect of Anti-MerTK Antibody Treatment on Colon Cancer In Vivo To determine the ability of anti-MerTK antibodies of the disclosure to reduce tumor burden in vivo, the following study was performed. In these experiments, 400,000 MC38 mouse colon cancer cells were implanted subcutaneously into the shaved right flank of C57BL/6 mice. When tumor sizes reached a volume of approximately 80-120 mm ³ , mice were divided into groups based on tumor volume for analysis with similar distribution of starting tumor volumes. Anti-MerTK antibodies MTK-29 and MTK33, or a control antibody were administered by intraperitoneal injection twice weekly at a dose of 10 mg/kg (N=9 per group). Concurrently, an anti-PDL1 antibody (clone BM1) was administered intraperitoneally twice weekly to all treatment groups at 3 mg/kg. Tumor volumes were measured three times a week using caliber. Mice were humanely euthanized when tumor volumes reached approximately 2000 mm ³ or when ulceration occurred. For these studies, two independent in vivo experiments were performed.

Figures 12A and 12B show that treatment of mice with anti-PDL1 antibody and either anti-MerTK antibody MTK-29 or MTK-33 was observed in mice treated with either anti-PDL1 antibody alone or control antibody. It shows that the rate of tumor growth (as indicated by tumor volume over time) was decreased compared to . These results demonstrate that when the anti-MerTK antibodies MTK-29 and MTK-33 were administered in combination with the anti-PDL1 antibody, the reduction in tumor volume compared to that observed after treatment with the anti-PDL1 antibody alone ( showed a synergistic effect in reducing tumor growth rate).

Another series of in vivo experiments were also performed using a combination of anti-PDL1 antibody and anti-MerTK antibody MTK-29 or anti-MerTK antibody MTK-33. As shown in Figure 13, administration of anti-PDL1 antibody results in a reduction in tumor volume compared to that observed with control antibody treatment. Administration of anti-PDL1 antibody in combination with either anti-MerTK antibody MTK-29 or MTK-33 significantly reduced tumor volume compared to mice administered anti-PDL1 antibody alone. Specifically, the anti-MerTK antibody MTK-29 administered in combination with the anti-PDL1 antibody resulted in significantly greater (p≤ 0.05) resulted in a decrease. Notably, treatment with anti-PDL1 antibody in combination with anti-MerTK antibody MTK-33 significantly increased the proliferation rate of MC38 colon cancer cells in these studies compared to that observed in mice treated with anti-PDL1 antibody alone. lowered. Animals treated with anti-MerTK antibody MTK-33 at 20 mg/kg as monotherapy also showed a reduction in tumor volume compared to that observed in control antibody-treated animals (data not shown). .

Figures 14A, 14B, 14C, and 14D (and Figures 15A, 15B, 15C, and 15D) show control, anti-PDL1 antibody alone, anti-PDL1 antibody combined with anti-MerTK antibody MTK-29, and anti-PDL1 antibody with anti-PDL1 antibody, respectively. Shown is the difference in tumor growth rate (tumor volume over time) of individual mice in combination with the anti-MerTK antibody MTK-33. Figures 14A, 14B, 14C, and 14D are plotted using a linear scale on the y-axis. Figures 15A, 15B, 15C, and 15D are the same results plotted using Log2 memory on the y-axis. As shown in these figures, combined treatment with an anti-PDL1 antibody and either the anti-MerTK antibodies MTK-29 or MTK-33 resulted in near complete tumors in 4 of the 9 mice examined in these studies. brought about a recession.

Figure 16 shows survival curves of tumor-bearing mice from these studies. The median survival of mice treated with the control antibody was 28 days, the median survival of mice treated with the anti-PDL1 antibody alone was 35 days, and the anti-PDL1 antibody was combined with the anti-MerTK antibody MTK-29. The median survival time of mice treated with the anti-PDL1 antibody was 35 days, and the median survival time of mice treated with the anti-PDL1 antibody in combination with the anti-MerTK antibody MTK-33 exceeded the final 42 days after tumor implantation. , 6 out of 9 mice were still alive after 42 days of this combination treatment. Taken together, the results shown in Figures 12A, 12B, 13, 14A, 14B, 14C, 14D, 15A, 15B, 15C, 15D, and 16 demonstrate the combination of anti-MerTK antibodies MTK-29 and MTK-33 with anti-PDL1 antibody. was shown to enhance efficacy in inhibiting tumor growth and improving cancer immunotherapy compared to treatment with anti-PDL1 antibody alone.

Example 20 Modulation of Proinflammatory Cytokine or Chemokine Production in Mice The effects of anti-MerTK antibodies of the disclosure on inflammatory cytokine or chemokine production in mice were examined as follows. Control or anti-MerTK antibodies MTK-24, MTK-29, MTK-30, or MTK-33 were administered to C57BL/6 mice by intraperitoneal injection at a dose of 20 mg/kg (N=5 per group). One hour later, each animal was bled for measurement of changes in inflammatory cytokine or chemokine levels. The LEGENDplex Mouse Inflammatory Chemokine Panel (Biolegend, Catalog #740451) and the LEGENDplex Mouse Macrophage/Microglia Panel (Biolegend, Catalog #740846) were used according to the manufacturer's instructions as follows. Briefly, mouse serum samples were diluted 4-fold in assay buffer. A standard cocktail was serially diluted in assay buffer. For the standard solution setup, 25 μl of matrix B, 25 μl of standard solution and 25 μl of mixed beads were added. For the sample well setup, 25 μl of assay buffer, 25 μl of diluted serum sample, and 25 μl of mixed beads were added. Each plate was placed on a plate shaker at 500 rpm for 2 hours. After washing the plate, 25 μl of detection antibody was added to each well, then the plate was placed on a plate shaker for 1 hour. 25 μl of SA-PE was added and then the plate was shaken for 30 minutes. After washing, samples were resuspended in 1X wash buffer, acquired on a BD FACS CantoII (Becton Dickinson, San Jose, Calif.) and data analyzed with LEGENDplex software (Biolegend).

Figures 17A, 17B, 17C, 17D, and 17E show KC (CXCL1), MCP1 (CCL2), MIP-1α (CCL3), MIP-1β (CCL4), and MIP-1α (CCL4) in mice after administration of an anti-MerTK antibody of the present disclosure. Levels of IL-6 are shown, respectively. As shown in these figures, levels of each of these chemokines or cytokines increased in response to anti-MerTK antibodies MTK-24, MTK-29, MTK-30, and MTK-33 administration in mice compared to control antibodies. increased compared to that observed in treated mice. These results indicated that the anti-MerTK antibodies MTK-24, MTK-29, MTK-30, or MTK-33 induced the production of inflammatory chemokines or cytokines in mouse peripheral cells in a MerTK-dependent manner. These results also demonstrate that the anti-MerTK antibodies of the disclosure are effective in increasing inflammatory cytokine/chemokine levels in vivo, thus suggesting that the anti-MerTK antibodies of the disclosure are active in anti-tumor immune responses. Further evidence is provided that it is effective in

Example 21 Modulation of Inflammatory Cytokine or Chemokine Production in Non-Human Primates The effect of anti-MerTK antibodies of the disclosure on in vivo production of inflammatory cytokines or chemokines was examined in cynomolgus monkeys as follows. Anti-MerTK antibodies MTK-15, MTK-16, or MTK-21 were administered to cynomolgus monkeys by intravenous injection at a dose of 10 mg/kg (N=3 per group). Blood was collected before administration (predose) and 1 hour, 6 hours, 12 hours, 24 hours, 72 hours, 168 hours and 216 hours after administration. Inflammatory cytokine and chemokine levels were determined using the LEGENDplex NHP Inflammation Panel (Biolegend, Catalog #740389) and the LEGENDplex NHP Chemokine/Cytokine Panel (Biolegend, Catalog #740317) according to the manufacturer's instructions. Briefly, plasma samples were diluted 4-fold with assay buffer. A standard cocktail was serially diluted in assay buffer. For the standard well setup, 25 μl of matrix B, 25 μl of standard solution, and 25 μl of mixed beads were added. For the sample well setup, 25 μl of assay buffer, 25 μl of diluted plasma sample, and 25 μl of mixed beads were added. Plates were placed on a plate shaker at 500 rpm for 2 hours. After washing, 25 μl of detection antibody was added and then the plate was shaken for 1 hour. 25 μl of SA-PE was added and then the plate was shaken for 30 minutes. After washing, samples were resuspended in 1X wash buffer, acquired on a BD FACS CantoII (Becton Dickinson, San Jose, Calif.) and data analyzed with LEGENDplex software (Biolegend). Graphs were plotted as fold increase in cytokine/chemokine levels at each specified time point relative to pre-dose cytokine/chemokine levels.

Figures 18A, 18B, 18C, and 18D show MCP1 (CCL2), MIP-1β ( CCL4), TNF, and IFN levels change over time. Peak levels of MCP1 occurred approximately 12 hours after dosing. Administration of the anti-MerTK antibody MTK-15 increased levels of MIP-1β, TNF, and IFN up to 72 hours after administration. Taken together, these results indicated that anti-MerTK antibodies MTK15, MTK-16, or MTK-21 increased the production of inflammatory chemokines or cytokines in cynomolgus monkey peripheral cells in a MerTK-dependent manner. These results further demonstrate that the anti-MerTK antibodies of the disclosure are effective in increasing MCP1, MIP-1b, TNF, and IFN, which are inflammatory cytokines/chemokines, in vivo in non-human primates. showed that

anti-MerTk antibody MTK-15 or anti-MerTK antibody MTK-29 (both of which block binding of ProS to MerTK but not Gas6 to MerTK, both bind to the Ig2 and FN1 domains of MerTK); Two additional studies were performed in cynomolgus monkeys or treated with the anti-MerTK antibody MTK-16, which blocks the binding of both ProS and Gas6 to MerTK and binds to the Ig1 domain of MerTK. In these preliminary studies, animals treated with anti-MerTK antibody MTK-16 showed reduced systemic toxicity compared to animals treated with anti-MerTK antibody MTK-15 or anti-MerTK antibody MTK-29. These preliminary results indicate that anti-MerTK antibodies that block the binding of both ProS and Gas6 to MerTK are better than anti-MerTK antibodies that block ProS binding to MerTK but not Gas6 binding to MerTK. It was suggested that it may provide an excellent in vivo safety profile. These preliminary results indicate that anti-MerTK antibodies that bind to the Ig1 domain of MerTK may provide a superior in vivo safety profile than anti-MerTK antibodies that bind to both the Ig2 and FN1 domains of MerTK. was also suggested.

Example 22: Phosphorylated AKT Assay in Human Macrophages The ability of anti-MerTK antibodies of the disclosure to block phosphorylated AKT signaling in the presence of human Gas6 (huGas6) protein was assessed as follows. Differentiated human macrophages were treated with 100 nM dexamethasone (Sigma-Aldrich, Cat# D4902) and 10 ng/ml huM-CSF (R&D systems, Cat#216MC25CF) for 2 days to polarize into M2c macrophages. 100,000 cells were seeded in 96-well plates. The next day, cells were serum starved for 4 hours. After treating the cells with anti-MerTK antibody for 30 minutes at 37° C., 200 nM huGas6 (R&D systems, cat#885-GSB-050) was added to the cells. After 30 minutes of incubation, cells were lysed and subjected to homogeneous time-resolved fluorescence (HTRF) assays of phosphorylated AKT (pAKT) (CisBio, Cat.#63ADK082PEG) or total AKT (CisBio, Cat.#64NKTPEG) according to the manufacturer's instructions. identified according to pAKT signal was normalized to total AKT signal to quantify final pAKT activity.

Figures 19A and 19B illustrate exemplary anti-MerTK antibodies of the present disclosure (MTK-9, MTK-12, MTK-15, MTK-16, MTK-18, MTK-20, MTK-21, MTK-22, MTK- 29, and MTK-33) dose-dependently inhibited Gas6-mediated pAKT activity. Table 18 above shows IC50 values identified for blocking of Gas6-mediated pAKT activity by anti-MerTK antibodies. As shown in Table 18, anti-MerTK antibodies of the disclosure inhibited ligand (eg, Gas6)-mediated MerTK signaling. These results further demonstrated that the anti-MerTK antibodies of the present disclosure inhibit Gas6-mediated MerTK signaling with IC50 values ranging from 0.019 nM to 7.74 nM, as measured by pAKT levels.

Example 23: Domain Binding Analysis of Anti-MerTK Antibodies The following studies were performed to analyze the binding sites of various anti-MerTK antibodies of this disclosure with respect to human MerTK.

MerTKs are members of the TAM family, whose members include an N-terminal region (N), two immunoglobulin-like domains (Ig1 and Ig2), two fibronectin type III domains (FN1 and FN2), a juxtamembrane region (JM ), and an intracellular tyrosine kinase domain. MerTK also contains an unstructured region at both the N-terminus of the protein and the juxtamembrane (JM) region of the MerTK protein, where cleavage in the juxtamembrane region results in the release of the soluble MerTK extracellular domain (ECD). be The human MerTK ECD can be divided into the following domains, whose amino acid sequences are shown in Table 19 below.

Another member of the TAM family, the Axl protein shares a common domain structure with MerTK and has the following domains and related amino acid sequences in its ECD.

In these experiments, a series of chimeric proteins were recombinantly expressed in which various domains of human MerTK were exchanged for the corresponding human Axl domains. The resulting chimeric proteins were recombinantly expressed in Expi293 cells, and then the binding of various anti-MerTK antibodies of this disclosure was analyzed for their ability to bind Axl/MerTK domain-swapped chimeras. Encoding domain-swapped chimeras and deletion mutants with signal sequences (MGWSCIILFLVATATGVHS (SEQ ID NO: 461) for MerTK constructs and MGWSCILFLVATATG (SEQ ID NO: 462) for Axl constructs) and linker + His + Avi tag (GGSGHHHHHHGGGGLNDIFEAQKIEWHE, SEQ ID NO: 463) DNA was prepared by gene synthesis and cloned into the expression vector pcDNAtopo3.4 (GeneArt, ThermoFisher). Expi293 cells were transfected with 20 μg of plasmid and ExpiFectamine according to recommended procedures (ThermoFisher). Transfected cells were grown in 20 mL cultures at 37° C. and 5% CO ₂ for 4 days with shaking. Cells were pelleted by centrifugation and the supernatant was vacuum filtered through a 0.2 μM filter.

Table 21 shows the construction of various Axl/MerTK domain-swapped chimeras generated for use in these studies. In Table 21, M (MerTK) or A (Axl) indicate proteins whose particular domains are included (ie, exchanged) in the corresponding chimeric protein constructs. N (N-terminal domain), Ig1 (immunoglobulin-like domain 1), Ig2 (immunoglobulin-like domain 2), FN1 (fibronectin type III domain 1), FN2 (fibronectin type III domain 2), and JM (juxtamembrane domain) .

Binding of anti-MerTK antibodies of the disclosure to these domain-swapped chimeras or deletion mutants (prepared as described above) was examined by surface plasmon resonance (SPR) using Carterra LSA. Purified anti-MerTK antibodies were immobilized in duplicate to HC30M chips (Carterra) by amine coupling according to the manufacturer's instructions (described above). Supernatants containing constructs were diluted 1:1 in running buffer containing 0.5 mg/mL BSA (HBS-TE, Carterra) and injected over the immobilized antibody. After injection of each construct, the surface was regenerated with 10 mM glycine pH 2.0. Sensorgrams were analyzed using Carterra epitope software to identify patterns of construct binding. Loss of binding to MerTK constructs in which domains were deleted or exchanged from Axl and/or increased binding to Axl constructs with MerTK domains exchanged was assessed. Data from these studies were used to construct a domain binding map of anti-MerTK antibodies and their binding to various domains of human MerTK.

In addition to the anti-MerTK antibodies of the present disclosure, the following anti-MerTK antibodies were also used in these studies: rat anti-mouse MerTK antibody DS5MMER (eBioscience, clone ID DS5MMER, rat IgG2a), mouse anti-human MerTK antibody H1 (BioLegend , clone ID: 590H11G1E3, mouse IgG1), mouse anti-human MerTK antibody H2 (R&D systems, clone ID: 125518, mouse IgG2b), mouse anti-human MerTK antibody H3 (R&D systems, clone ID 125508, mouse IgG2b), mouse anti-human MerTK antibody H6 (eBioscience, clone ID: A3KCAT, mouse IgG1), mouse anti-human MerTK antibody H7 (Sino Biological, clone ID: 09, mouse IgG2b), human anti-human MerTK antibody M6 (disclosed in WO2016/106221, huIgG1 LALAPS), and the human anti-human MerTK antibody CDX AB3000 (disclosed in WO2020/106461).

The results of these binding studies are shown in Table 22 above. As shown in Table 22, anti-MerTK antibody H6 bound to chimeric protein constructs containing the N-terminal region of human MerTK. The anti-MerTK antibodies MTK-10, MTK-16, MTK-21, MTK-25, MTK-33 and M6 bound constructs containing the MerTK Ig1 domain. Anti-MerTK antibody MTK-22 bound to a chimeric protein construct containing MerTK Ig1, but binding of anti-MerTK antibody MTK-22 was affected by the presence of the MerTK FN1 domain. The anti-MerTK antibodies MTK-06, MTK-15, MTK-29, MTK-30, CDX AB3000, H1, and H2 bound only to chimeric protein constructs containing both the MerTK Ig2 and FN1 domains. Anti-MerTK antibodies H3 and H7 bound to a chimeric protein construct containing the juxtamembrane region of MerTK. None of the anti-MerTK antibodies tested above bound to the ECD domain of human Axl (data not shown).

These results indicated that the anti-MetTK antibodies of this disclosure that block binding of both Gas6 and ProS to MerTK generally bind to the Ig1 domain of human MerTK. These results also showed that anti-MerTK antibodies of the present disclosure that block binding of ProS alone to MerTK generally bound to both domain combinations of Ig2/FN1.

Example 24 Effect of Anti-MerTK Antibody Treatment in a Transgenic Mouse Colon Cancer Model The effect of anti-MerTK antibodies on tumor growth in vivo was investigated using an in vivo mouse colon cancer model in which mice are transgenic containing human MerTK. I went as follows. MC38 mouse cancer cells were subcutaneously implanted into the shaved right flank of huMerTK knock-in (KI) mice (Ozgene, Perth, Australia) to introduce human MerTK into the mouse genome. When tumor sizes reached a volume of approximately 80-130 mm ³ , mice were treated with 10 mg/kg MTK-33 + 3 mg/kg anti-PDL1 (clone BM1), 10 mg/kg MTK-16 + 3 mg/kg anti-PDL1, 3 mg/kg. /kg anti-PDL1 alone or 10 mg/kg control antibody twice weekly. Tumor volumes were measured three times weekly.

FIG. 20A compares the combination of anti-PDL1 antibody with either anti-MerTK antibody MTK-16 or anti-MerTK antibody MTK-33 observed in mice treated with either anti-PDL1 antibody alone or control antibody. and moderately decreased tumor growth rate. FIG. 20B shows the tumor growth of individual mice in each group, with anti-PDL1 combined treatment with either MTK-16 or MTK-33, 3 or 4 out of 9 mice developed tumors. completely regressed. Thus, this data indicates that the combination of the anti-MerTK antibodies MTK-16 or MTK-33, which bind to human MerTK, and the anti-PDL1 antibody improved efficacy in inhibiting tumor growth.

Example 25: Humanization of Mouse Anti-MERTK Mouse Antibodies Humanized variants of certain parental mouse anti-MerTK antibodies of the present disclosure were generated as follows.

親マウス抗ＭｅｒＴＫ抗体ＭＴＫ－１６は、アミノ酸配列：ＬＩＱＬＶＱＳＧＰＥＬＫＫＰＧＥＴＶＫＩＳＣＫＡＳＧＹＴＦＴＮＨＧＭＮＷＶＫＱＤＰＧＫＧＬＫＷＭＧＷＩＮＴＹＴＧＥＰＴＹＡＤＤＦＫＧＲＦＶＦＳＭＥＴＳＡＳＡＡＦＬＱＩＮＮＬＫＮＥＤＴＡＴＹＦＣＡＲＫＧＶＴＡＡＲＹＦＤＹＷＧＱＧＴＴＬＴＶＳＳ（配列番号２０）を含む重鎖可変領域、及びアミノ酸配列：ＤＩＶＭＴＱＳＰＫＦＭＳＴＳＶＧＤＲＶＳＩＴＣＫＡＳＱＮＶＲＴＡＶＡＷＹＫＫＫＰＧＱＳＰＫＡＬＩＮＬＡＳＮＲＨＴＧＶＰＤＲＦＴＧＳＧＳＧＴＤＦＴＬＴＩＳＮＶＱＳＥＤＬＡＤＹＦＣＬＱＨＷＮＹＰＬＴＦＧＧＧＴＫＬＥＩＫ（配列番号５５）を含む軽鎖可変領域を含む。

親マウス抗ＭｅｒＴＫ抗体ＭＴＫ－３３は、アミノ酸配列：ＱＶＱＬＱＱＰＧＰＥＬＶＲＰＧＴＳＶＫＬＳＣＫＡＳＧＹＴＦＴＳＹＷＭＨＷＩＫＱＲＰＧＱＧＬＥＷＩＧＶＩＤＰＳＤＮＹＩＮＹＮＱＫＦＫＧＫＡＴＬＴＶＤＴＳＳＳＴＡＹＬＱＬＳＳＬＴＳＥＤＳＡＶＹＹＣＡＲＥＡＧＴＲＧＹＦＤＹＷＧＱＧＴＴＬＴＶＳＳ（配列番号３７）を含む重鎖可変領域、及びアミノ酸配列：ＳＩＶＭＴＱＴＰＫＦＬＬＶＳＡＧＤＲＶＩＩＴＣＫＡＳＱＳＶＳＮＴＶＡＷＹＱＱＫＰＧＱＳＰＫＬＬＩＹＹＡＳＮＲＹＴＧＶＰＤＲＦＴＧＳＧＹＧＴＤＦＴＦＴＩＳＴＶＱＡＥＤＬＡＶＹＦＣＱＱＤＹＲＳＰＦＴＦＧＳＧＴＱＬＥＭＫ（配列番号７２）を含む軽鎖可変領域を含む。

親マウス抗ＭｅｒＴＫ抗体ＭＴＫ－１５は、アミノ酸配列：ＱＩＱＬＶＱＳＧＰＥＬＫＫＰＧＥＴＶＫＩＳＣＫＡＳＧＹＴＦＴＮＹＧＶＨＷＶＫＱＡＰＧＫＧＬＫＷＭＧＷＩＮＴＹＴＧＥＰＴＹＡＤＤＦＫＧＲＦＡＦＳＬＥＴＳＡＳＴＡＹＬＱＩＮＮＬＫＮＥＤＭＡＴＹＦＣＡＲＧＮＲＹＡＹＭＤＹＷＧＱＧＴＳＶＴＶＳＳ（配列番号１９）を含む重鎖可変領域、及びアミノ酸配列：ＱＩＶＬＳＱＳＰＡＩＬＳＡＳＰＧＥＫＶＴＭＴＣＲＡＳＳＳＶＳＹＭＨＷＹＱＱＫＳＧＳＳＰＫＰＷＩＹＡＴＳＮＬＡＳＧＶＰＡＲＦＳＧＳＧＳＧＴＳＹＳＬＴＩＳＲＶＥＡＥＤＡＡＴＹＹＣＱＱＷＳＳＮＰＲＴＦＧＧＧＴＫＬＥＩＫ（配列番号５４）を含む軽鎖可変領域を含む。

親マウス抗ＭｅｒＴＫ抗体ＭＴＫ－２９は、アミノ酸配列：ＱＩＱＬＶＱＳＧＰＥＬＫＫＰＧＥＴＶＫＩＳＣＫＳＳＧＦＴＦＴＴＹＧＭＳＷＶＫＱＡＰＧＫＧＬＫＷＭＧＷＩＮＴＹＳＧＶＰＴＹＴＤＤＦＫＧＲＦＡＦＳＬＥＴＳＡＳＴＡＳＬＱＩＮＮＬＫＮＥＤＴＡＴＹＦＣＡＲＹＴＮＹＧＹＦＤＹＷＧＱＧＴＴＬＴＶＳＳ（配列番号３３）を含む重鎖可変領域、及びアミノ酸配列：ＱＩＶＬＳＱＳＰＡＩＬＳＡＳＰＧＥＫＶＴＭＴＣＲＡＴＳＳＶＧＹＭＨＷＹＱＱＫＰＧＳＳＰＫＰＷＩＹＡＴＳＮＬＡＳＧＶＰＡＲＦＳＧＳＧＳＧＴＳＹＳＬＴＩＳＲＶＥＡＥＨＡＡＴＹＹＣＱＱＷＧＳＮＰＦＴＦＧＳＧＴＫＬＥＩＫ（配列番号６８）を含む軽鎖可変領域を含む。

One method of humanizing non-human antibodies is to graft CDRs from a non-human (eg, murine) antibody onto a human antibody acceptor framework. Such CDR grafting can result in diminished or complete loss of the affinity of the humanized antibody for its target due to perturbation of its framework. As a result, certain amino acid residues in the human framework are replaced with amino acid residues from the corresponding position in the mouse antibody framework (called backmutations), and are attenuated or lost upon humanization. It may be necessary to restore previously established affinities. Accordingly, amino acid residues to be substituted in the context of a selected human antibody germline acceptor framework must be determined such that the humanized antibody substantially retains function and paratope. Additionally, retention or improvement of thermal stability and solubility is desired for good manufacturability and downstream development.

Briefly, the amino acid sequences of the VH and VL of the murine anti-MerTK monoclonal antibody undergoing humanization were obtained from IMGT (http://www.imgt.org/), functional sequences of human VL, VH, LJ, and HJ. A comparison was made with the germline amino acid sequence. Pseudogenes and open reading frames were excluded from these analyses. For each mouse monoclonal antibody (query), the 1 or 2 most similar VH and 1 most similar VL germline amino acid sequences were selected and combined with the most similar VJ and HJ genes, one or Two humanized amino acid sequences were produced. CDRs grafted into the human framework were defined according to the AbM definition.

Structure-based antibody modeling was applied to the process of humanizing the murine anti-MerTK monoclonal antibodies MTK-15 and MTK-29 using the BioMOE module of MOE (Molecular Operating Environment, Chemical Computing Group, Montreal, Canada). Briefly, the amino acid sequences of the VH and VL of mouse monoclonal antibodies MTK-15 and MTK-29 were derived from human VL, VH, LJ, HJ from IMGT (http://www.imgt.org/) as described above. Comparisons were made with functional germline amino acid sequences. The 3 most similar VH and 3 most similar VL germline amino acid sequences were selected and combined with the most similar VJ and HJ genes to produce 5-8 humanized amino acid sequences.

This query and humanized amino acid sequence was used to generate an Fv homology model using the BioMOE module of MOE or the Antibody Modeler module (Molecular Operating Environment, Chemical Computing Group, Montreal, Canada). AMBER10:EHT forcefield analysis was used for energy minimization of the entire antibody homology modeling process. Based on the obtained Fv homology model, molecular descriptors such as interaction energy between VL and VH, coordinate-based isoelectric point (3D pI), hydrophobic patches, and charged surface areas were provided by MOE. calculated, analyzed, and sorted by the scoring metric. These molecular descriptors were used to prioritize humanized monoclonal antibodies for downstream experimental procedures including protein expression, purification, binding affinity testing, and functional assays.

The BioMOE module of MOE provides Mutation Site Properties, a tool for visualizing and classifying potential backmutated residues. In this context, a backmutation is defined as an amino acid substitution back into the original query amino acid sequence that replaces the humanized amino acid sequence. Using this tool, the original query (reference) was individually compared with the selected humanized variants in terms of both primary amino acid sequence and 3D structure of the 3D Fv homology model.

The changes between the reference (i.e., parent) antibody and the humanized variant are measured by differences in amino acid type, interaction potential with CDR residues, impact potential of VL/VH pairing, and changes in and near the CDRs. Classification was based on potential changes in hydrophobicity and charged surface area.

Mutations near the CDRs or near the VL/VH interface with significant charge differences or involving strong H-bond interactions were evaluated individually and significantly disruptive mutations were assigned to residues of the original query. returned.

Affinity maturation of the humanized anti-MerTK antibodies MTK-33, MTK-29, and MTK-16 was also performed. Briefly, certain amino acid residues in the heavy or light chain were selectively mutated and variants with improved binding were selected through additional rounds of screening. This process simultaneously improved specificity, interspecies cross-reactivity, and developability profile. Characterization of the affinity matured anti-MerTK antibodies described herein included SPR affinity measurements in Carterra LSA and efferocytosis blocking assays in human macrophages. After multiple rounds of affinity maturation, anti-MerTK antibodies with the desired affinities were obtained. The amino acid sequences of the variable heavy chain (VH) and variable light chain (VL) are shown in Table 23 (MTK-15 variants), Table 24 (MTK-16 variants), Table 25 (MTK-29 variants), and Table 26 (MTK -33 variant). In Tables 23, 24, 25 and 26 the hypervariable regions (HVRs) of each chain are underlined.

Tables 27 and 28 provide the heavy chain HVR and light chain HVR amino acid sequences, respectively, for the anti-MerTK antibody MTK-15 variants. Tables 29 and 30 provide the heavy chain HVR and light chain HVR amino acid sequences, respectively, for anti-MerTK antibody MTK-16 variants. Tables 31 and 32 provide the heavy chain HVR and light chain HVR amino acid sequences, respectively, for the anti-MerTK antibody MTK-29 variants. Tables 33 and 34 provide the heavy chain HVR and light chain HVR amino acid sequences, respectively, for the anti-MerTK antibody MTK-33 variants.

Example 26 Blocking Efferocytosis by Humanized and Affinity-Matured Anti-MerTK Antibodies It was evaluated using the method described in 11. Differentiated human macrophages were treated with 100 nM dexamethasone (Sigma-Aldrich) and 10 μg/ml huM-CSF (R&D systems) for 2 days. 50,000 polarized macrophages were seeded in 96-well plates. Humanized or affinity matured anti-MerTK antibodies were titrated to a final concentration range of 66.6 nM to 4 pM, after which each serially diluted antibody was added to each well for 30 minutes at 37°C.

Staurosporine-induced apoptotic Jurkat cells were labeled with pHrodo (ThermoFisher) and then added to each well at a 1:4 ratio (1 macrophage:4 Jurkat cells) for 1 hour. After washing the plates with PBS, cells were stained with APC-conjugated anti-human CD14 for 30 minutes on ice in the dark. Cells were then washed twice with FACS buffer (PBS + 2% FBS) and flow cytometry was performed on a BD FACSCanto II. Data were analyzed using FlowJo software. In these experiments, a baseline efferocytosis level was established using macrophages cultured in medium alone, which was set at 100% efferocytosis activity. Relative efferocytosis activity was calculated as the percentage of efferocytosis observed in cells treated with medium alone compared to that observed in cells treated with anti-MerTK antibody. The results of these tests are shown in Table 35 below.

As shown in Table 35, the humanized and affinity matured anti-MerTK antibodies of the disclosure were effective in blocking efferocytosis by human macrophages and exhibited various IC50 values. Certain affinity matured variants of the anti-MerTK antibodies MTK-15, MTK-16, and MTK-33 exhibited IC50 values similar to the corresponding parental anti-MerTK antibodies (see Example 11 above). Certain other affinity matured variants of anti-MerTK antibodies showed lower IC50 values for blocking efferocytosis (e.g. MTK-15.1, MTK-15.4, MTK-15.5, MTK -15.6, MTK-15.7, MTK-15.8, MTK-15.10, MTK-15.13, MTK-15.15, MTK-16.1, and MTK-33.15). Affinity matured variants of MTK-15 exhibit IC50 values ranging from 0.228 nM to 2.4 nM, affinity matured variants of MTK-16 exhibit IC50 values ranging from 0.36 nM to 1.01 nM, and MTK-29 Affinity matured variants exhibited IC50 values ranging from 0.5 nM to 1.12 nM, and affinity matured variants of MTK-33 exhibited IC50 values ranging from 0.41 nM to 23.9 nM.

Example 27: Binding Kinetics of Humanized and Affinity-Matured Anti-MerTK Antibodies The binding kinetics of humanized and affinity-matured anti-MerTK antibodies of the present disclosure to human, mouse, and cynomolgus monkey MerTK proteins were determined as follows. evaluated to Briefly, anti-MerTK antibody was prepared at 300 μl/well by diluting to 10 μg/ml with 10 mM acetic acid, pH 4.25 (Carterra, Salt Lake City, Utah). HC200M sensor chips (Carterra) were reconstituted with 1:1:1 mixed 100 mM MES pH 5.5, 100 mM sulfo-NHS, 400 mM EDC (all MES pH 5.5, 100 μl of each mixed in a vial) was injected for 7 minutes to activate just before running the assay. After switching to the multi-channel array flow cell, the antibody was injected for 15 minutes into the activated chip of the 96-spot array. Remaining unconjugated active groups on the chip were then blocked by injecting 1 M ethanolamine pH 8.5 (Carterra) for 7 minutes using a single-channel flow cell.

After priming with running buffer (HBS-TE, Carterra) containing 0.5 mg/ml BSA (Sigma), immobilized anti-MerTK antibody was applied to extracellular recombinant MerTK including human, cynomolgus monkey, and mouse orthologues described above. They were examined for their ability to bind several forms of domains.

Affinity estimates were generated by injecting each analyte over the antibody array using a single-channel flow cell. MerTK analytes were diluted in running buffer to 33.3, 100, and 300 nM and injected sequentially from lowest to highest concentration without regeneration. Two buffer blanks were run between each series (one per series). Data were processed and analyzed using NextGenKIT high-throughput kinetic analysis software (Carterra). In these experiments, the anti-MerTK antibody was human IgG1 isotype with Fc variant LALAPS.

Equilibrium dissociation constants (K _D ) were then calculated from the fitted association and dissociation rate constants (k-on and k-off) for the anti-MerTK antibodies of the disclosure. The K _D values obtained from these experiments are summarized in Table 36 below.

These results indicated that the humanized and affinity-matured anti-MerTK antibodies of the present disclosure exhibited varying affinities for human, cynomolgus monkey, and mouse MerTK proteins.

These results also demonstrated that the humanized and affinity-matured anti-MerTK antibodies of the present disclosure exhibit varying cross-species binding specificities and cross-reactivities to human, mouse, and cynomolgus monkey MerTK. In particular, the affinities of the anti-MerTK antibodies of the disclosure for binding to human MerTK ranged from 0.1 nM to 86 nM, and the affinities of the anti-MerTK antibodies of the disclosure for binding to cynomolgus monkey MerTK ranged from 0.3 nM to 1450 nM. And, the affinities of anti-MerTK antibodies of the disclosure for binding to mouse MerTK ranged from 44 nM to 2800 nM. Compared to the parental anti-MerTK antibody MTK-15, certain affinity-matured anti-MerTK antibody MTK-15 variants had increased binding activity to mouse MerTK, ranging from 114 nM to 2800 nM.

Table 37 below shows the amino acid sequences of various human heavy chain immunoglobulin Fc variants.

The amino acid sequence of the human IgG1 light chain constant region is shown below.
RTVAAPSVFIFPPSDEQLKSGTASVVCLLNNFYPREAKVQWKVDNALQSGNSQESVTEQDSKDSTYSLSSTLTLSKADYEKHKVYACEVTHQGLSSPVTKSFNRGEC (SEQ ID NO: 412).

The full-length heavy chain amino acid sequences of certain anti-MerTK antibodies of this disclosure are shown in Table 38 below.

The MTK-16.1 light chain amino acid sequence is shown below.
ＤＩＱＭＴＱＳＰＳＳＬＳＡＳＶＧＤＲＶＴＩＴＣＫＡＳＱＮＶＲＴＡＶＡＷＹＱＱＫＰＧＫＡＰＫＲＬＩＹＬＡＳＮＲＨＴＧＶＰＳＲＦＳＧＳＧＳＧＴＥＦＴＬＴＩＳＮＬＱＰＥＤＦＡＴＹＹＣＬＱＨＷＮＹＰＬＴＦＧＧＧＴＫＶＥＩＫＲＴＶＡＡＰＳＶＦＩＦＰＰＳＤＥＱＬＫＳＧＴＡＳＶＶＣＬＬＮＮＦＹＰＲＥＡＫＶＱＷＫＶＤＮＡＬＱＳＧＮＳＱＥＳＶＴＥＱＤＳＫＤＳＴＹＳＬＳＳＴＬＴＬＳＫＡＤＹＥＫＨＫＶＹＡＣＥＶＴＨＱＧＬＳＳＰＶＴＫＳＦＮＲＧＥＣ（配列番号４２１）

The full-length heavy chain amino acid sequences of certain anti-MerTK antibodies of this disclosure are shown in Table 39 below.

The MTK-16.2 light chain amino acid sequence is shown below.
ＤＩＱＭＴＱＳＰＳＳＬＳＡＳＶＧＤＲＶＴＩＴＣＲＡＳＱＮＶＲＴＡＶＡＷＹＱＱＫＰＧＫＡＰＫＲＬＩＹＬＡＳＮＲＨＴＧＶＰＳＲＦＳＧＳＧＳＧＴＥＦＴＬＴＩＳＮＬＱＰＥＤＦＡＴＹＹＣＬＱＨＷＮＹＰＬＴＦＧＧＧＴＫＬＥＩＫＲＴＶＡＡＰＳＶＦＩＦＰＰＳＤＥＱＬＫＳＧＴＡＳＶＶＣＬＬＮＮＦＹＰＲＥＡＫＶＱＷＫＶＤＮＡＬＱＳＧＮＳＱＥＳＶＴＥＱＤＳＫＤＳＴＹＳＬＳＳＴＬＴＬＳＫＡＤＹＥＫＨＫＶＹＡＣＥＶＴＨＱＧＬＳＳＰＶＴＫＳＦＮＲＧＥＣ（配列番号４３０）

The full-length heavy chain amino acid sequences of certain anti-MerTK antibodies of this disclosure are shown in Table 40 below.

The MTK-33.1 light chain amino acid sequence is shown below.
ＤＩＱＭＴＱＳＰＳＳＬＳＡＳＶＧＤＲＶＴＩＴＣＱＡＳＱＳＶＳＮＴＶＡＷＹＱＱＫＰＧＫＡＰＫＬＬＩＹＹＡＳＬＲＹＴＧＶＰＳＲＦＳＧＳＧＳＧＴＤＦＴＦＴＩＳＳＬＱＰＥＤＩＡＴＹＹＣＱＱＤＹＲＳＰＦＴＦＧＱＧＴＫＬＥＩＫＲＴＶＡＡＰＳＶＦＩＦＰＰＳＤＥＱＬＫＳＧＴＡＳＶＶＣＬＬＮＮＦＹＰＲＥＡＫＶＱＷＫＶＤＮＡＬＱＳＧＮＳＱＥＳＶＴＥＱＤＳＫＤＳＴＹＳＬＳＳＴＬＴＬＳＫＡＤＹＥＫＨＫＶＹＡＣＥＶＴＨＱＧＬＳＳＰＶＴＫＳＦＮＲＧＥＣ（配列番号４３９）

The full-length heavy chain amino acid sequences of certain anti-MerTK antibodies of this disclosure are shown in Table 41 below.

The MTK-33.12 light chain amino acid sequence is shown below.
ＤＩＱＭＴＱＳＰＳＳＬＳＡＳＶＧＤＲＶＴＩＴＣＱＡＳＱＳＶＳＮＴＶＡＷＹＱＱＫＰＧＫＡＰＫＬＬＩＹＹＡＳＮＲＹＴＧＶＰＳＲＦＳＧＳＧＳＧＴＤＦＴＦＴＩＳＳＬＱＰＥＤＩＡＴＹＹＣＲＱＤＴＲＳＰＦＴＦＧＱＧＴＫＬＥＬＫＲＴＶＡＡＰＳＶＦＩＦＰＰＳＤＥＱＬＫＳＧＴＡＳＶＶＣＬＬＮＮＦＹＰＲＥＡＫＶＱＷＫＶＤＮＡＬＱＳＧＮＳＱＥＳＶＴＥＱＤＳＫＤＳＴＹＳＬＳＳＴＬＴＬＳＫＡＤＹＥＫＨＫＶＹＡＣＥＶＴＨＱＧＬＳＳＰＶＴＫＳＦＮＲＧＥＣ（配列番号４４８）

The full-length heavy chain amino acid sequences of certain anti-MerTK antibodies of this disclosure are shown in Table 42 below.

The MTK-33.10 light chain amino acid sequence is shown below.

Claims (117)

An isolated antibody that binds to human Mer tyrosine kinase (MerTK), said antibody reducing efferocytosis by phagocytic cells. 2. The antibody of claim 1, which reduces efferocytosis by at least 50% compared to an isotype control antibody. 3. The antibody of claim 2, which reduces efferocytosis by at least 60%, at least 70%, at least 80%, at least 90%, or at least 95%. 2. The antibody of claim 1, which reduces efferocytosis with an IC50 value of 0.13 nM to 30 nM. 5. The antibody of claim 4, which reduces efferocytosis with an IC50 value of 0.13 nM to 1 nM, 1 nM to 5 nM, 5 nM to 10 nM, or 10 nM to 30 nM. The antibody of any one of claims 1-5, wherein the phagocytic cell is a macrophage, a tumor-associated macrophage, or a dendritic cell. The antibody of any one of claims 1-6, which reduces binding of ProS to MerTK. reduces binding of ProS to MerTK by at least 20%, at least 25%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95% 8. The antibody of claim 7. 8. The antibody of claim 7, which reduces binding of ProS to MerTK with an IC50 value of 0.58 nM to 25.9 nM. 10. The antibody of claim 9, which reduces ProS binding to MerTK with an IC50 value of 0.58 nM to 1 nM, 1 nM to 2.5 nM, 2.5 nM to 5 nM, 5 nM to 10 nM, or 10 nM to 25 nM. The antibody of any one of claims 1-6, which reduces binding of Gas6 to MerTK. reduces binding of Gas6 to MerTK by at least 20%, at least 25%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95% 12. The antibody of claim 11. 12. The antibody of claim 11, which reduces binding of Gas6 to MerTK with an IC50 value of 0.29 nM to 32 nM. 14. The antibody of claim 13, which reduces binding of Gas6 to MerTK with an IC50 value of 0.29 nM to 1 nM, 1 nM to 5 nM, 5 nM to 10 nM, 10 nM to 25 nM, or 25 nM to 32 nM. 7. The antibody of any one of claims 1-6, which reduces binding of ProS to MerTK and reduces binding of Gas6 to MerTK. reduces binding of ProS to MerTK by at least 20%, at least 25%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95% with at least 20%, at least 25%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95% 16. The antibody of claim 15, which lowers. 16. The antibody of claim 15, which reduces binding of ProS to MerTK with an IC50 value of 0.58 nM to 25.9 nM and reduces binding of Gas6 to MetTK with an IC50 value of 0.29 nM to 32 nM. 18. The antibody of any one of claims 1-17, which binds human MerTK and mouse MerTK, binds human MerTK and cynomolgus monkey MerTK, or binds human MerTK, mouse MerTK and cynomolgus monkey MerTK. The antibody of any one of claims 1-18, which binds to human MerTK with a binding affinity of 1.4 nM to 81 nM. 20. The antibody of claim 18 or 19, which binds to cynomolgus monkey MerTK with a binding affinity of 1.6 nM to 107 nM. The antibody of any one of claims 19-20, which binds to mouse MerTK with a binding affinity of 30 nM to 186 nM. 22. The antibody of any one of claims 1-21, which reduces Gas6-mediated phosphorylation of AKT. 23. The antibody of claim 22, which reduces Gas6-mediated phosphorylation of AKT with an IC50 value of 0.019 nM to 7.74 nM. Gas6-mediated phosphorylation of AKT was quantified with IC50 values of 0.019 nM-0.25 nM, 0.25 nM-0.5 nM, 0.5 nM-1 nM, 1 nM-2.5 nM, 2.5 nM-5 nM, or 5 nM-7. 24. The antibody of claim 23, which lowers at 0.74 nM. 25. The antibody of any one of claims 1-24, which increases or induces M1-like macrophage polarization. 26. The antibody of any one of claims 1-25, which increases macrophage expression of one or more inflammatory cytokines. 27. The antibody of claim 26, which increases macrophage expression of TNF, IFN, IL-6, IL-1, IL-12, CXCL-1, MCP1, MIP-1α and/or MIP-1β. An isolated antibody that binds to human MerTK, said antibody comprising a heavy chain variable region and a light chain variable region, said heavy chain variable region comprising:
a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:83,
b) an HVR-H2 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs:99, 329, 330, 331, 332 and 333; HVR-H3 comprising an amino acid sequence selected from the group consisting of
wherein the light chain variable region is
d) HVR-L1 comprising an amino acid sequence selected from the group consisting of SEQ ID NOS: 158, 340, 341, 342, 343 and 344;
e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:187; and f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:210. 30. The antibody of claim 29,
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:83, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:99, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:138, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:83, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:329, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:334, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 83, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 330, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 138, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 83, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 329, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 138, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 83, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 329, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 138, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:83, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:329, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:335, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 83, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 331, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 138, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 83, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 329, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 138, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 83, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 329, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 336, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:83, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:329, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:337, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 83, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 332, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 338, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:83, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:333, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:334, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 83, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 332, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 336, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:83, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:329, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:339, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 210; or (a) the amino acid sequence of SEQ ID NO: 83. (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:329; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:138; (d) HVR- comprising the amino acid sequence of SEQ ID NO:158 L1, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:187, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:210. 30. The antibody of claim 28 or 29, comprising a heavy chain variable domain ( _VH ) and a light chain variable domain ( _VL ), wherein said _VH and _VL are selected from the group consisting of Said antibody:
a V _H comprising the amino acid sequence of SEQ ID NO: 19 and a V _L comprising the amino acid sequence of SEQ ID NO: 54;
V _H comprising the amino acid sequence of SEQ ID NO:234 and V _L comprising the amino acid sequence of SEQ ID NO:247,
V _H comprising the amino acid sequence of SEQ ID NO:235 and V _L comprising the amino acid sequence of SEQ ID NO:247,
V _H comprising the amino acid sequence of SEQ ID NO:236 and V _L comprising the amino acid sequence of SEQ ID NO:248,
V _H comprising the amino acid sequence of SEQ ID NO:236 and V _L comprising the amino acid sequence of SEQ ID NO:249,
V _H comprising the amino acid sequence of SEQ ID NO:237 and V _L comprising the amino acid sequence of SEQ ID NO:249,
V _H comprising the amino acid sequence of SEQ ID NO:238 and V _L comprising the amino acid sequence of SEQ ID NO:249,
V _H comprising the amino acid sequence of SEQ ID NO:239 and V _L comprising the amino acid sequence of SEQ ID NO:250,
V _H comprising the amino acid sequence of SEQ ID NO:240 and V _L comprising the amino acid sequence of SEQ ID NO:251,
V _H comprising the amino acid sequence of SEQ ID NO:241 and V _L comprising the amino acid sequence of SEQ ID NO:252,
V _H comprising the amino acid sequence of SEQ ID NO:242 and V _L comprising the amino acid sequence of SEQ ID NO:249,
V _H comprising the amino acid sequence of SEQ ID NO:243 and V _L comprising the amino acid sequence of SEQ ID NO:247,
V _H comprising the amino acid sequence of SEQ ID NO:244 and V _L comprising the amino acid sequence of SEQ ID NO:251,
V _H comprising the amino acid sequence of SEQ ID NO:245 and V _L comprising the amino acid sequence of SEQ ID NO:253,
A V _H comprising the amino acid sequence of SEQ ID NO:246 and a V _L comprising the amino acid sequence of SEQ ID NO:247, and a V _H comprising the amino acid sequence of SEQ ID NO:246 and a V _L comprising the amino acid sequence of SEQ ID NO:254. An isolated antibody that binds to human MerTK, said antibody comprising a heavy chain variable region and a light chain variable region, said heavy chain variable region comprising:
a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:84,
b) HVR-H2 comprising an amino acid sequence selected from the group consisting of SEQ ID NO: 99 and 329, and c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 139,
wherein the light chain variable region is
d) HVR-L1 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 169 and 345;
e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:195; and f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:219. 32. The antibody of claim 31,
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:84;
(b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:329;
(c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 139;
(d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 169;
(e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 195; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 219; or (a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 84;
(b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:99;
(c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 139;
(d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:345;
(e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:195; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:219. 33. The antibody of claim 31 or 32, comprising a heavy chain variable domain ( _VH ) and a light chain variable domain ( _VL ), wherein said _VH and _VL are selected from the group consisting of Said antibody:
V _H comprising the amino acid sequence of SEQ ID NO:255 and V _L comprising the amino acid sequence of SEQ ID NO:257,
A V _H comprising the amino acid sequence of SEQ ID NO:256 and a V _L comprising the amino acid sequence of SEQ ID NO:258. An isolated antibody that binds to human MerTK, said antibody comprising a heavy chain variable region and a light chain variable region, said heavy chain variable region comprising:
a) HVR-H1 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 95, 346 and 347,
b) an HVR-H2 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 119, 348, 349, 350, 351, 352, 353, and 354; and c) from the group consisting of SEQ ID NOs: 151, 355, and 356. comprising an HVR-H3 comprising a selected amino acid sequence, and
wherein the light chain variable region is
d) HVR-L1 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 181, 341, 357 and 358;
e) HVR-L2 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 187 and 359; and f) HVR-L3 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs: 208, 360, 361, and 362. said antibody. 35. The antibody of claim 34,
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 95, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 119, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 151, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 208;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 346, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 348, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 355, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 360;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 95, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 119, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 355, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 361;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 95, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 349, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 356, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 362;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 95, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 119, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 356, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:359; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:362;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 346, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 119, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 356, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:359; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:362;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 95, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 350, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 356, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:359; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:362;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 347, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 119, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 356, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:359; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:362;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 95, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 119, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 356, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 362;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 95, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 352, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 356, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 362;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 95, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 353, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 356, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:359; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:362;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 346, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 354, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 356, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:359; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:363;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 346, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 348, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 356, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:359; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:362;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 346, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 354, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 356, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 187; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 362; or (a) the amino acid sequence of SEQ ID NO: 95. (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 348; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 151; (d) HVR- comprising the amino acid sequence of SEQ ID NO: 181 L1, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:187, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:208. 36. The antibody of claim 34 or 35, comprising a heavy chain variable domain ( _VH ) and a light chain variable domain ( _VL ), wherein said _VH and _VL are selected from the group consisting of Said antibody:
a V _H comprising the amino acid sequence of SEQ ID NO:33 and a V _L comprising the amino acid sequence of SEQ ID NO:68;
V _H comprising the amino acid sequence of SEQ ID NO:259 and V _L comprising the amino acid sequence of SEQ ID NO:274,
V _H comprising the amino acid sequence of SEQ ID NO:260 and V _L comprising the amino acid sequence of SEQ ID NO:275,
V _H comprising the amino acid sequence of SEQ ID NO:261 and V _L comprising the amino acid sequence of SEQ ID NO:276,
V _H comprising the amino acid sequence of SEQ ID NO:262 and V _L comprising the amino acid sequence of SEQ ID NO:277,
V _H comprising the amino acid sequence of SEQ ID NO:263 and V _L comprising the amino acid sequence of SEQ ID NO:277,
V _H comprising the amino acid sequence of SEQ ID NO:264 and V _L comprising the amino acid sequence of SEQ ID NO:277,
V _H comprising the amino acid sequence of SEQ ID NO:265 and V _L comprising the amino acid sequence of SEQ ID NO:277,
V _H comprising the amino acid sequence of SEQ ID NO:266 and V _L comprising the amino acid sequence of SEQ ID NO:277,
V _H comprising the amino acid sequence of SEQ ID NO:267 and V _L comprising the amino acid sequence of SEQ ID NO:278,
V _H comprising the amino acid sequence of SEQ ID NO:268 and V _L comprising the amino acid sequence of SEQ ID NO:279,
V _H comprising the amino acid sequence of SEQ ID NO:269 and V _L comprising the amino acid sequence of SEQ ID NO:279,
V _H comprising the amino acid sequence of SEQ ID NO:264 and V _L comprising the amino acid sequence of SEQ ID NO:280,
V _H comprising the amino acid sequence of SEQ ID NO:270 and V _L comprising the amino acid sequence of SEQ ID NO:281,
V _H comprising the amino acid sequence of SEQ ID NO:265 and V _L comprising the amino acid sequence of SEQ ID NO:282,
V _H comprising the amino acid sequence of SEQ ID NO:264 and V _L comprising the amino acid sequence of SEQ ID NO:283,
V _H comprising the amino acid sequence of SEQ ID NO:271 and V _L comprising the amino acid sequence of SEQ ID NO:284,
V _H comprising the amino acid sequence of SEQ ID NO:272 and V _L comprising the amino acid sequence of SEQ ID NO:285,
V _H comprising the amino acid sequence of SEQ ID NO:271 and V _L comprising the amino acid sequence of SEQ ID NO:286,
V _H comprising the amino acid sequence of SEQ ID NO:273 and V _L comprising the amino acid sequence of SEQ ID NO:287,
A V _H comprising the amino acid sequence of SEQ ID NO:273 and a V _L comprising the amino acid sequence of SEQ ID NO:288, and a V _H comprising the amino acid sequence of SEQ ID NO:273 and a V _L comprising the amino acid sequence of SEQ ID NO:289. An isolated antibody that binds to human MerTK, said antibody comprising a heavy chain variable region and a light chain variable region, said heavy chain variable region comprising:
a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:90,
b) HVR-H2 comprising an amino acid sequence selected from the group consisting of SEQ ID NOS: 122, 364, 365, 366, 367, and 368; and c) selected from the group consisting of SEQ ID NOS: 155, 373, 374, and 375 comprising an HVR-H3 comprising an amino acid sequence that
wherein the light chain variable region is
d) HVR-L1 comprising an amino acid sequence selected from the group consisting of SEQ ID NOS: 184, 376, 377, 378, 379, 380, 381, 382, 383, 384, 385, 386 and 387;
e) an HVR-L2 comprising an amino acid sequence selected from the group consisting of SEQ ID NOs:203, 388, 389, 390, and 391; and f) an amino acid selected from the group consisting of SEQ ID NOs:231, 392, 393, and 394. Said antibody comprising a HVR-L3 containing sequence. 38. The antibody of claim 37,
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 122, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:231;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 364, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 373, (d) SEQ ID NO: HVR-L1 comprising the amino acid sequence of 376, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:388, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:231;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 364, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:231;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 364, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 374, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:231;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 95, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 119, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 356, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:359; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:362;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 365, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 203; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 392;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 364, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155, (d) SEQ ID NO: HVR-L1 comprising the amino acid sequence of 376, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:389, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:231;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 364, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:231;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 366, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:231;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 364, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 373, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:231;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 367, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:231;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 368, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:231;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 364, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 374, (d) SEQ ID NO: HVR-L1 comprising the amino acid sequence of 384, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:231;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 368, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 203; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 393;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 364, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:231;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 368, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:231;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 369, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 203; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 394;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 370, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 203; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 394;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 371, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:394;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 368, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155, (d) SEQ ID NO: HVR-L1 comprising the amino acid sequence of 385, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:394;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 368, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO: 203; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO: 395;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 368, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155, (d) SEQ ID NO: HVR-L1 comprising the amino acid sequence of 378, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:390, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:394;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 372, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:391; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:394;
(a) HVR-H1 comprising the amino acid sequence of SEQ ID NO: 90, (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 368, (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 375, (d) SEQ ID NO: (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203; and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:394; or (a) the amino acid sequence of SEQ ID NO:90. (b) HVR-H2 comprising the amino acid sequence of SEQ ID NO: 368; (c) HVR-H3 comprising the amino acid sequence of SEQ ID NO: 155; (d) HVR- comprising the amino acid sequence of SEQ ID NO: 387 L1, (e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203, and (f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:394. 39. The antibody of claim 37 or 38, comprising a heavy chain variable domain ( _VH ) and a light chain variable domain ( _VL ), wherein said _VH and _VL are selected from the group consisting of Said antibody:
a V _H comprising the amino acid sequence of SEQ ID NO:37 and a V _L comprising the amino acid sequence of SEQ ID NO:72;
V _H comprising the amino acid sequence of SEQ ID NO:290 and V _L comprising the amino acid sequence of SEQ ID NO:309,
V _H comprising the amino acid sequence of SEQ ID NO:291 and V _L comprising the amino acid sequence of SEQ ID NO:310,
V _H comprising the amino acid sequence of SEQ ID NO:292 and V _L comprising the amino acid sequence of SEQ ID NO:311,
V _H comprising the amino acid sequence of SEQ ID NO:293 and V _L comprising the amino acid sequence of SEQ ID NO:312,
V _H comprising the amino acid sequence of SEQ ID NO:294 and V _L comprising the amino acid sequence of SEQ ID NO:313,
V _H comprising the amino acid sequence of SEQ ID NO:295 and V _L comprising the amino acid sequence of SEQ ID NO:314,
V _H comprising the amino acid sequence of SEQ ID NO:296 and V _L comprising the amino acid sequence of SEQ ID NO:315,
V _H comprising the amino acid sequence of SEQ ID NO:290 and V _L comprising the amino acid sequence of SEQ ID NO:316,
V _H comprising the amino acid sequence of SEQ ID NO:297 and V _L comprising the amino acid sequence of SEQ ID NO:317,
V _H comprising the amino acid sequence of SEQ ID NO:298 and V _L comprising the amino acid sequence of SEQ ID NO:318,
V _H comprising the amino acid sequence of SEQ ID NO:292 and V _L comprising the amino acid sequence of SEQ ID NO:319,
V _H comprising the amino acid sequence of SEQ ID NO:299 and V _L comprising the amino acid sequence of SEQ ID NO:320,
V _H comprising the amino acid sequence of SEQ ID NO:300 and V _L comprising the amino acid sequence of SEQ ID NO:311,
V _H comprising the amino acid sequence of SEQ ID NO:301 and V _L comprising the amino acid sequence of SEQ ID NO:321,
V _H comprising the amino acid sequence of SEQ ID NO:302 and V _L comprising the amino acid sequence of SEQ ID NO:322,
V _H comprising the amino acid sequence of SEQ ID NO:303 and V _L comprising the amino acid sequence of SEQ ID NO:311,
V _H comprising the amino acid sequence of SEQ ID NO:304 and V _L comprising the amino acid sequence of SEQ ID NO:322,
V _H comprising the amino acid sequence of SEQ ID NO:305 and V _L comprising the amino acid sequence of SEQ ID NO:322,
V _H comprising the amino acid sequence of SEQ ID NO:301 and V _L comprising the amino acid sequence of SEQ ID NO:323,
V _H comprising the amino acid sequence of SEQ ID NO:301 and V _L comprising the amino acid sequence of SEQ ID NO:324,
V _H comprising the amino acid sequence of SEQ ID NO:301 and V _L comprising the amino acid sequence of SEQ ID NO:325,
V _H comprising the amino acid sequence of SEQ ID NO:306 and V _L comprising the amino acid sequence of SEQ ID NO:326,
A V _H comprising the amino acid sequence of SEQ ID NO:307 and a V _L comprising the amino acid sequence of SEQ ID NO:327, and a V _H comprising the amino acid sequence of SEQ ID NO:308 and a V _L comprising the amino acid sequence of SEQ ID NO:328. An isolated antibody that binds to human MerTK, said antibody comprising a heavy chain variable region and a light chain variable region, said heavy chain variable region comprising:
a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:90,
b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:368, and c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:155,
wherein the light chain variable region is
d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:383;
e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203; and f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:231. 41. The antibody of claim 40, comprising a heavy chain variable domain ( _VH ) and a light chain variable domain ( _VL ), wherein said _VH comprises the amino acid sequence of SEQ ID NO: 298 and said _VL comprises , the antibody comprising the amino acid sequence of SEQ ID NO:318. 42. The antibody of claim 40 or 41,
(a) a heavy chain comprising the amino acid sequence of SEQ ID NO:466 and a light chain comprising the amino acid sequence of SEQ ID NO:472, or (b) a heavy chain comprising the amino acid sequence of SEQ ID NO:467 and a light chain comprising the amino acid sequence of SEQ ID NO:472 Said antibody, comprising 42. The antibody of claim 40 or 41,
(a) a heavy chain comprising the amino acid sequence of SEQ ID NO:464 and a light chain comprising the amino acid sequence of SEQ ID NO:472;
(b) a heavy chain comprising the amino acid sequence of SEQ ID NO:465 and a light chain comprising the amino acid sequence of SEQ ID NO:472;
(c) a heavy chain comprising the amino acid sequence of SEQ ID NO:468 and a light chain comprising the amino acid sequence of SEQ ID NO:472, or (d) a heavy chain comprising the amino acid sequence of SEQ ID NO:469 and a light chain comprising the amino acid sequence of SEQ ID NO:472 Said antibody, comprising An isolated antibody that binds to human MerTK, said antibody comprising a heavy chain variable region and a light chain variable region, said heavy chain variable region comprising:
a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:84,
b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:99, and c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:139, and
wherein the light chain variable region is
d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:345;
e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:195; and f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:219. 45. The antibody of claim 44, comprising a heavy chain variable domain ( _VH ) and a light chain variable domain ( _VL ), wherein said _VH comprises the amino acid sequence of SEQ ID NO: 256 and said _VL comprises , the antibody comprising the amino acid sequence of SEQ ID NO:258. 46. The antibody of claim 44 or 45,
(a) a heavy chain comprising the amino acid sequence of SEQ ID NO:424 and a light chain comprising the amino acid sequence of SEQ ID NO:430, or (b) a heavy chain comprising the amino acid sequence of SEQ ID NO:425 and a light chain comprising the amino acid sequence of SEQ ID NO:430 Said antibody, comprising 46. The antibody of claim 44 or 45,
(a) a heavy chain comprising the amino acid sequence of SEQ ID NO:422 and a light chain comprising the amino acid sequence of SEQ ID NO:430;
(b) a heavy chain comprising the amino acid sequence of SEQ ID NO:423 and a light chain comprising the amino acid sequence of SEQ ID NO:430;
(c) a heavy chain comprising the amino acid sequence of SEQ ID NO:426 and a light chain comprising the amino acid sequence of SEQ ID NO:430, or (d) a heavy chain comprising the amino acid sequence of SEQ ID NO:427 and a light chain comprising the amino acid sequence of SEQ ID NO:430 Said antibody, comprising An isolated antibody that binds to human MerTK, said antibody comprising a heavy chain variable region and a light chain variable region, said heavy chain variable region comprising:
a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:90,
b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:368, and c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:155,
wherein the light chain variable region is
d) HVR-L1 comprising the amino acid sequence of SEQ ID NO:376;
e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:203; and f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:393. 49. The antibody of claim 48, comprising a heavy chain variable domain ( _VH ) and a light chain variable domain ( _VL ), wherein said _VH comprises the amino acid sequence of SEQ ID NO:299 and said _VL comprises , the antibody comprising the amino acid sequence of SEQ ID NO:320. 50. The antibody of claim 48 or 49,
(a) a heavy chain comprising the amino acid sequence of SEQ ID NO:442 and a light chain comprising the amino acid sequence of SEQ ID NO:448, or (b) a heavy chain comprising the amino acid sequence of SEQ ID NO:443 and a light chain comprising the amino acid sequence of SEQ ID NO:448 Said antibody, comprising 50. The antibody of claim 48 or 49,
(a) a heavy chain comprising the amino acid sequence of SEQ ID NO:440 and a light chain comprising the amino acid sequence of SEQ ID NO:448;
(b) a heavy chain comprising the amino acid sequence of SEQ ID NO:441 and a light chain comprising the amino acid sequence of SEQ ID NO:448;
(c) a heavy chain comprising the amino acid sequence of SEQ ID NO:444 and a light chain comprising the amino acid sequence of SEQ ID NO:448, or (d) a heavy chain comprising the amino acid sequence of SEQ ID NO:445 and a light chain comprising the amino acid sequence of SEQ ID NO:448 Said antibody, comprising An isolated antibody that binds to human MerTK, said antibody comprising a heavy chain variable region and a light chain variable region, said heavy chain variable region comprising:
a) HVR-H1 comprising the amino acid sequence of SEQ ID NO:84,
b) HVR-H2 comprising the amino acid sequence of SEQ ID NO:329, and c) HVR-H3 comprising the amino acid sequence of SEQ ID NO:139,
wherein the light chain variable region is
d) HVR-L1 comprising the amino acid sequence of SEQ ID NO: 169;
e) HVR-L2 comprising the amino acid sequence of SEQ ID NO:195; and f) HVR-L3 comprising the amino acid sequence of SEQ ID NO:219. 53. The antibody of claim 52, comprising a heavy chain variable domain ( _VH ) and a light chain variable domain ( _VL ), wherein said _VH comprises the amino acid sequence of SEQ ID NO: 255 and said _VL comprises , the antibody comprising the amino acid sequence of SEQ ID NO:257. 54. The antibody of claim 52 or 53,
(a) a heavy chain comprising the amino acid sequence of SEQ ID NO:415 and a light chain comprising the amino acid sequence of SEQ ID NO:421, or (b) a heavy chain comprising the amino acid sequence of SEQ ID NO:416 and a light chain comprising the amino acid sequence of SEQ ID NO:421 Said antibody, comprising 54. The antibody of claim 52 or 53,
(a) a heavy chain comprising the amino acid sequence of SEQ ID NO:413 and a light chain comprising the amino acid sequence of SEQ ID NO:421;
(b) a heavy chain comprising the amino acid sequence of SEQ ID NO:414 and a light chain comprising the amino acid sequence of SEQ ID NO:421;
(c) a heavy chain comprising the amino acid sequence of SEQ ID NO:417 and a light chain comprising the amino acid sequence of SEQ ID NO:421, or (d) a heavy chain comprising the amino acid sequence of SEQ ID NO:418 and a light chain comprising the amino acid sequence of SEQ ID NO:421 Said antibody, comprising An isolated antibody that binds to human MerTK, said antibody comprising a heavy chain variable region and a light chain variable region, said heavy chain variable region comprising:
a) SEQ. and HVR-H1 comprising an amino acid sequence selected from the group consisting of 98;
b) SEQ. HVR-H2 comprising an amino acid sequence selected from the group consisting of 122, 123 and 124; amino acids selected from the group consisting of 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, and 157 comprising an HVR-H3 comprising a sequence, and
wherein the light chain variable region is
d) SEQ. HVR-L1 comprising an amino acid sequence selected from the group consisting of 181, 182, 183, 184, 185, and 186;
e) an amino acid selected from the group consisting of SEQ ID NOs: 187, 188, 189, 190, 191, 192, 193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203, 204, and 205 HVR-L2 comprising sequences and f) SEQ ID NOs: 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 230, 231, 232 and 233, comprising an HVR-L3 comprising an amino acid sequence. 57. The antibody of claim 56, comprising HVR-H1, HVR-H2, HVR-H3, HVR-L1, HVR-L2, and HVR-L3, wherein said HVR-H1, HVR-H2, HVR-H3 , HVR-L1, HVR-L2, and HVR-L3 have the amino acid sequences:
(i) SEQ ID NOs: 75, 99, 125, 158, 187, and 207, respectively;
(ii) SEQ ID NOs: 76, 100, 126, 159, 187, and 208, respectively;
(iii) SEQ ID NOS: 77, 101, 127, 160, 188, and 209, respectively;
(iv) SEQ ID NOs: 75, 99, 128, 158, 187, and 210, respectively;
(v) SEQ ID NOS: 78, 102, 129, 161, 189, and 211, respectively;
(vi) SEQ ID NOs: 75, 103, 130, 158, 187, and 212, respectively;
(vii) SEQ ID NOs: 77, 101, 127, 162, 188, and 209, respectively;
(viii) SEQ ID NOs: 75, 99, 131, 163, 187, and 213, respectively;
(ix) SEQ ID NOs: 79, 104, 132, 164, 190, and 214, respectively;
(x) SEQ ID NOs: 80, 105, 133, 165, 191, and 215, respectively;
(xi) SEQ ID NOs: 81, 106, 134, 166, 192, and 216, respectively;
(xii) SEQ ID NOs: 82, 107, 135, 167, 193, and 217, respectively;
(xiii) SEQ ID NOS: 77, 108, 136, 167, 194, and 209, respectively;
(xiv) SEQ ID NOS: 75, 109, 137, 168, 187, and 218, respectively;
(xv) SEQ ID NOs: 83, 99, 138, 158, 187, and 210, respectively;
(xvi) SEQ ID NOs: 84, 99, 139, 169, 195, and 219, respectively;
(xvii) SEQ ID NOs: 85, 99, 140, 170, 196, and 220, respectively;
(xviii) SEQ ID NOs: 86, 99, 141, 171, 191, and 221, respectively;
(xix) SEQ ID NOs: 87, 110, 142, 172, 197, and 222, respectively;
(xx) SEQ ID NOs: 88, 99, 143, 173, 191, and 223, respectively;
(xxi) SEQ ID NOs: 89, 111, 143, 173, 198, and 221, respectively;
(xxii) SEQ ID NOS: 90, 112, 144, 174, 199 and 224, respectively;
(xxiii) SEQ ID NOs: 91, 113, 145, 175, 200, and 225, respectively;
(xxiv) SEQ ID NOS: 90, 114, 146, 176, 201, and 226, respectively;
(xxv) SEQ ID NOs: 92, 115, 147, 177, 195, and 227, respectively;
(xxvi) SEQ ID NOs: 93, 116, 148, 178, 188, and 209, respectively;
(xxvii) SEQ ID NOS: 94, 117, 149, 179, 195, and 228, respectively;
(xxviii) SEQ ID NOS: 95, 118, 150, 180, 187 and 229, respectively;
(xxix) SEQ ID NOs: 95, 119, 151, 181, 187, and 208, respectively;
(xxx) SEQ ID NOS: 90, 120, 152, 182, 202, and 230, respectively;
(xxxi) SEQ ID NOS: 96, 118, 153, 183, 202, and 230, respectively;
(xxxii) SEQ ID NOS: 96, 121, 154, 181, 187, and 210, respectively;
(xxxiii) SEQ ID NOs: 90, 122, 155, 184, 203, and 231, respectively;
(xxxiv) SEQ ID NOS: 90, 122, 155, 184, 203, and 231, respectively;
(xxxv) SEQ. An isolated antibody that binds to human MerTK, comprising: MTK-10, MTK-11, MTK-12, MTK-13, MTK-14, MTK-15, MTK-16, MTK-17, MTK-18, MTK-19, MTK-20, MTK-21, MTK- 22, MTK-23, MTK-24, MTK-25, MTK-26, MTK-27, MTK-28, MTK-29, MTK-30, MTK-31, MTK-32, MTK-33, MTK-34, MTK-35, MTK-36, MTK-15.1, MTK-15.2, MTK-15.3, MTK-15.4, MTK-15.5, MTK-15.6, MTK-15.7, MTK-15.8, MTK-15.9, MTK-15.10, MTK-15.11, MTK-15.12, MTK-15.13, MTK-15.14, and MTK-15.15, MTK -16.1 and MTK-16.2, MTK-29.1, MTK-29.2, MTK-29.3, MTK-29.4, MTK-29.5, MTK-29.6, MTK-29 .7, MTK-29.8, MTK-29.9, MTK-29.10, MTK-29.11, MTK-29.12, MTK-29.13, MTK-29.14, MTK-29.15 , MTK-29.16, MTK-29.17, MTK-29.18, MTK-29.19, MTK-29.20, and MTK-29.21, MTK-33.1, MTK-33.2, MTK-33.3, MTK-33.4, MTK-33.5, MTK-33.6, MTK-33.7, MTK-33.8, MTK-33.9, MTK-33.10, MTK- 33.11, MTK-33.12, MTK-33.13, MTK-33.14, MTK-33.15, MTK-33.16, MTK-33.17, MTK-33.18, MTK-33. 19, MTK-33.20, MTK-33.21, MTK-33.22, MTK-33.23, or MTK-33.24 antibodies HVR-H1, HVR-H2, HVR-H3, HVR-L1, Said antibody comprising HVR-L2 and HVR-L3 sequences. 59. The antibody of claim 58, wherein the HVR is a Kabat-defined HVR, a Chothia-defined HVR, or an AbM-defined HVR. The antibody of any one of claims 1-27, 58 and 59, wherein the antibody is SEQ ID NO: 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 , 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 234-246, 255 , 256, 259-379, and 290-308 or SEQ ID NOS: 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18 , 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 234-246, 255, 256 , 259-379, and 290-308. 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 247-254, 257, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, an amino acid sequence selected from the group consisting of 258, 274-289, and 309-328 or 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 247-254, 257, 258, Said antibody comprising a light chain variable region comprising amino acid sequences having at least 90% identity to 274-289 and 309-328. An isolated antibody that binds to human MerTK, said antibody comprising a heavy chain variable region and a light chain variable region, said heavy chain variable region comprising SEQ ID NOs: 5, 6, 7, 8, 9, 10 , 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35 , 36, 37, 38, 39, 234-246, 255, 256, 259-379, and 290-308. An isolated antibody that binds to human MerTK, said antibody comprising a heavy chain variable region and a light chain variable region, said light chain variable region comprising SEQ ID NOs: 40, 41, 42, 43, 44, 45 , 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70 , 71, 72, 73, 74, 247-254, 257, 258, 274-289, and 309-328. 64. The antibody of any one of claims 1-27 and 58-63, wherein said antibody comprises a heavy chain variable region and a light chain variable region, said heavy chain variable region and light chain variable region comprising: SEQ ID NOs:5 and 40, respectively; SEQ ID NOs:6 and 41, respectively; SEQ ID NOs:7 and 42, respectively; SEQ ID NOs:8 and 43, respectively; SEQ ID NOs:9 and 44, respectively; SEQ. 17 and 52, respectively, SEQ ID NOs: 18 and 53, respectively, SEQ ID NOs: 19 and 54, respectively, SEQ ID NOs: 20 and 55, respectively, SEQ ID NOs: 21 and 56, respectively, SEQ ID NOs: 22 and 57, respectively, SEQ ID NOs: 23 and 57, respectively. 58, SEQ ID NOs:24 and 59, respectively; SEQ ID NOs:25 and 60, respectively; SEQ ID NOs:26 and 61, respectively; SEQ ID NOs:27 and 62, respectively; SEQ ID NOs:28 and 63, respectively; 30 and 65 respectively, 31 and 66 respectively, 32 and 67 respectively, 33 and 68 respectively, 34 and 69 respectively, 35 and 70 respectively, 36 and 71, respectively, SEQ ID NOs: 37 and 72, respectively, SEQ ID NOs: 38 and 73, respectively, and SEQ ID NOs: 39 and 74, respectively. 65. An isolated antibody that binds to human MerTK, said antibody competitively inhibiting the binding of one or more of the antibodies of any one of claims 1-64 to bind human MerTK. An antibody, optionally competitively inhibiting the binding of MTK-10, MTK-12, MTK-13, MTK-19, MTK-20, or MTK-22. 65. An isolated antibody that binds to human MerTK, said antibody binding to an epitope of MerTK that is essentially the same as or overlaps with the antibody of any of claims 1-64 with respect to binding to human MerTK. and optionally binds to an epitope of MerTK essentially the same as or overlapping with MTK-10, MTK-12, MTK-13, MTK-19, MTK-20, or MTK-22. 67. The antibody of any one of claims 28-66, which reduces efferocytosis by phagocytic cells. 68. The antibody of claim 67, which reduces efferocytosis by at least 50% compared to an isotype control antibody. 69. The antibody of claim 68, which reduces efferocytosis by at least 60%, at least 70%, at least 80%, at least 90%, or at least 95%. 68. The antibody of claim 67, which reduces efferocytosis with an IC50 value of 0.13 nM to 30 nM. 71. The antibody of claim 70, which reduces efferocytosis with an IC50 value of 0.13 nM to 1 nM, 1 nM to 5 nM, 5 nM to 10 nM, or 10 nM to 30 nM. The antibody of any one of claims 67-71, wherein said phagocyte is a macrophage, tumor-associated macrophage, or dendritic cell. The antibody of any one of claims 28-72,
(i) reduces binding of ProS to MerTK but not Gas6 to MerTK, or (ii) reduces binding of ProS to MerTK and reduces binding of Gas6 to MerTK, said antibody. reduces binding of ProS to MerTK by at least 20%, at least 25%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95% 74. The antibody of claim 73. 74. The antibody of claim 73, which reduces binding of ProS to MerTK with an IC50 value of 0.58 nM to 25.9 nM. 76. The antibody of paragraph 75, which reduces binding of ProS to MerTK with an IC50 value of 0.58 nM to 1 nM, 1 nM to 2.5 nM, 2.5 nM to 5 nM, 5 nM to 10 nM, or 10 nM to 25 nM. The antibody of any one of claims 28-72, which reduces binding of Gas6 to MerTK. reduces binding of Gas6 to MerTK by at least 20%, at least 25%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95% 78. The antibody of claim 77. 78. The antibody of claim 77, which reduces binding of Gas6 to MerTK with an IC50 value of 0.29 nM to 32 nM. 80. The antibody of claim 79, which reduces binding of Gas6 to MerTK with an IC50 value of 0.29 nM to 1 nM, 1 nM to 5 nM, 5 nM to 10 nM, 10 nM to 25 nM, or 25 nM to 32 nM. 73. The antibody of any one of claims 28-72, which reduces binding of ProS to MerTK and reduces binding of Gas6 to MerTK. reduces binding of ProS to MerTK by at least 20%, at least 25%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95% with at least 20%, at least 25%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95% 82. The antibody of claim 81, which lowers. 82. The antibody of claim 81, which reduces binding of ProS to MerTK with an IC50 value of 0.58 nM to 25.9 nM and reduces binding of Gas6 to MetTK with an IC50 value of 0.29 nM to 32 nM. 84. The antibody of any one of claims 28-83, which binds human MerTK and mouse MerTK, binds human MerTK and cynomolgus monkey MerTK, or binds human MerTK, mouse MerTK and cynomolgus monkey MerTK. The antibody of any one of claims 28-84, which binds to human MerTK with a binding affinity of 1.4 nM to 81 nM. 86. The antibody of claim 84 or 85, which binds to cynomolgus monkey MerTK with a binding affinity of 1.6 nM to 107 nM. 87. The antibody of any one of claims 84-86, which binds to mouse MerTK with a binding affinity of 30 nM to 186 nM. 88. The antibody of any one of claims 28-87, which reduces Gas6-mediated phosphorylation of AKT. 89. The antibody of claim 88, which reduces Gas6-mediated phosphorylation of AKT with an IC50 value of 0.019 nM to 7.74 nM. Gas6-mediated phosphorylation of AKT was quantified with IC50 values of 0.019 nM-0.25 nM, 0.25 nM-0.5 nM, 0.5 nM-1 nM, 1 nM-2.5 nM, 2.5 nM-5 nM, or 5 nM-7. 90. The antibody of claim 89, which reduces at 0.74 nM. at least 1.7-fold, at least 2.3-fold, at least 2.4-fold, at least 5-fold, at least 7.7-fold, or at least 91. The antibody of any one of claims 1-6, 11-72, and 77-90, which is 8.5 times more effective. 92. The antibody of any one of claims 28-91, which increases or induces M1-like macrophage polarization. 93. The antibody of any one of claims 28-92, which increases macrophage expression of one or more inflammatory cytokines. 94. The antibody of claim 93, which increases macrophage expression of TNF, IFN, IL-6, IL-1, IL-12, CXCL-1, MCP1, MIP-1α and/or MIP-1β. The antibody of any one of claims 1-94, which also binds to cynomolgus monkey MerTK. 96. The antibody of any one of claims 1-95, which also binds mouse MerTK. 99. The antibody of any one of claims 1-98, which is a murine antibody, human antibody, humanized antibody, bispecific antibody, monoclonal antibody, multivalent antibody, conjugated antibody, or chimeric antibody. A humanized form of the antibody of any one of claims 1-96. 99. The antibody of any one of claims 1-98, which is of the IgG, IgM or IgA class. 100. The antibody of claim 99, which is of the IgG class and has the IgG1, IgG2, or IgG4 isotype. 101. The antibody of claim 100, which is of the IgGl isotype with an Fc amino acid sequence selected from the group consisting of SEQ ID NOs:396, 397, 398, 399, 400, and 401. 102. The antibody of any one of claims 1-101, which is a full length antibody. 103. The antibody of any one of claims 1-41, 44, 45, 48, 49, 52, 53, and 56-102, which is an antibody fragment. 104. The antibody of claim 103, wherein said fragment is a Fab, Fab', Fab'-SH, F(ab')2, Fv, or scFv fragment. An isolated nucleic acid comprising a nucleic acid sequence encoding the antibody of any one of claims 1-104. 106. A vector comprising the nucleic acid of claim 105. 107. An isolated host cell comprising the nucleic acid of claim 105 or the vector of claim 106. (i) a nucleic acid comprising a nucleic acid sequence encoding the VH of the antibody of any one of claims 1-104; and (ii) a nucleic acid comprising a nucleic acid sequence encoding the VL of the anti-MerTK antibody. Released host cells. 119. A method of producing an antibody that binds to human MerTK, said method comprising culturing the cell of claim 107 or 108 such that said antibody is produced. 110. The method of claim 109, further comprising recovering said antibody produced by said cell. 111. An antibody produced by the method of claim 109 or 110. A pharmaceutical composition comprising the antibody of any one of claims 1-104 and 111 and a pharmaceutically acceptable carrier. A method of treating an individual with cancer, comprising administering a therapeutically effective amount of an antibody according to any one of claims 1-104 and 111 or a pharmaceutical composition according to claim 112 to an individual in need thereof. The above method, comprising administering. 114. The method of claim 113, wherein the cancer is colon cancer, ovarian cancer, liver cancer, or endometrial cancer. 115. The method of claim 113 or 114, wherein said administering does not result in retinal lesions in said individual. 116. The method of any one of claims 113-115, further comprising administering an anti-PD-L1 antibody, an anti-PD-L2 antibody, or an anti-PD antibody to the individual. A method of detecting MerTK in a sample, said method comprising contacting said sample with the antibody of any one of claims 1-104 and 114.

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